Information recording/reproducing device using optical disk and method therefor and information recording system and information recording method

ABSTRACT

The sector synchronism of a timing generation section for generating data recording/reproducing timing is corrected at the address-mark detection timing of an address-mark detection section. Moreover, even if only one piece of address information having no error is not reproduced in the sector concerned, when at least one piece of address information having no error is reproduced in any of a predetermined number of sectors preceding the subject sector and at least one address mark is detected in the subject sector, the data recording/reproducing is permitted, and thus, the data is recorded/reproduced at a high speed and a high reliability even if an error rate of a physical address is deteriorated.

This application is a reissue of U.S. Pat. No. 6,975,570, issued Dec.13, 2005.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to an information recording reproducingapparatus and method for recording and/or reproducing information. Moreparticularly, the present invention relates to an optical-disk recordingapparatus and method for recording information in an optical diskserving as a recording medium, an optical-disk reproducing apparatus andmethod for reproducing information from an optical disk, and aninformation recording system and method using an optical-disk recordingapparatus in combination with an external unit. 2. Description of theBackground Art

An optical disk has gained attention as a large-capacityinformation-recording medium, and the development and commodification ofthe optical disk has progressed as an external memory device of acomputer or an audiovisual recording medium. In general, an optical diskhas spiral or concentric tracks formed on the disk surface. and recordsor reproduces information by applying a laser beam along the tracks.Moreover, each track is further divided into a plurality of sectorsrespectively serving as the minimum unit for recording or reproducinginformation data. Address information is previously recorded in eachsector so that a position on a disk can be univocally specified and arecording/reproducing apparatus makes it possible to record or reproduceinformation in sector units by reading address information from thedisk.

FIG. 18 is an illustration showing a data format in a sector of arewritable optical disk having been recently practically used in a caseof a DVD-RAM as an example. As shown in FIG. 18, a sector 1001 includesa header field 1002 and a data recording field 1003. The header field1002 has an address field 1004 and a mirror field 1005 and the addressfield 1004 is further divided into four address-fields, that is, firstto fourth address-fields 1004a, 1004b, 1004c, and 1004d. Eachaddress-field is constituted of address VFO fields VFOa, VFOb, VFOc, andVDOd (hereafter referred to as VFO field), address mark fields AMa, AMb,AMc, and AMd (hereafter referred to as AM), address information fieldsPIDa, PIDb, PIDc, and PIDd (hereafter referred to as PID), errordetection code: fields IEDa, IEDb, IEDc, and IEDd (hereafter referred toas IED), and, postamble fields PAa, PAb, PAc, and PAd (hereafterreferred to as PA) from the head in order. The data-recording field 1003is constituted of a gap field 1006, front guard field 1007, data VFOfield 1008, pre-sync code field 1009, data field 1010, data postamblefield 1011, rear guard field 1012, and buffer field 1013.

The contents and functions of each of the above fields are brieflydescribed below. First, the header field 1002 is an field for univocallyspecifying the position of each sector 1001 (that is, address) on anoptical disk, in which a pattern for recognizing an address by arecording/reproducing apparatus is recorded by previously forming anirregular pit shape in each field to be mentioned below. A single pitpattern for quickly performing lead-in of PLL in a reproductive systemof the apparatus is recorded in the VFO field (VFO) among fieldsconstituting the address fields 1004a to 1004d of the header field 1002.The single pit pattern uses, for example, a continuous pattern of4T-mark·4T-space. Here, “T” denotes a channel bit cycle, “mark” denotesa pit, that is, a concave portion, and “space” denotes a mirror, thatis, a convex portion. In this case, it is also permitted to reversedefinitions of a mark and a space.

A specific pattern showing a start of address information is recorded inthe address mark field (AM) and is used to correctly make bitesynchronization of each of the address information fields (PID)immediately after in the apparatus. Address information is recorded inthe address information field (PID). The address information includes atleast an address number for univocally specifying the position of eachsector on an optical disk and moreover, includes additional informationshowing the attributes of sectors and an nth address information fieldamong four address information fields in each sector.

An error detection code (parity) is recorded in the error detection codefield (IED) for detecting a bite error in the address information field(PID) immediately before. For example, a Reed-Solomon code or cycliccode is used as an error detection code, and address information errordetection coded data is reproduced by adding an error detection code toaddress information, and by passing through an error detecting circuit apattern of the reproduced address information error detection coded data(i.e., address information PID+error detection code IED), it is possibleto easily detect an error included in the pattern. A specific patternwhich indicates an end terminal of each address field is recorded in thepostamble fields (PA).

A modulation code obtained by modulating address information and binarydata of an error detection code in accordance with a predeterminedmodulation rule is actually recorded in each address information field(PID) and each error detection code field (IED). The rewritable opticaldisk of this example uses an 8/16RLL(2, 10) modulation code as amodulation code to be recorded in each address information field (PID),error detection code field (IED), and data field 1010 in the datarecording field 1003. In this case, 8/16 denotes that 8-bit binary datais converted to 16 channel bits. Moreover, RLL is the abbreviation forRun Length Limited and denotes that a run length, namely, the number ofsymbols O to be inserted between symbols 1 is finite when expressing achannel code by NRZ (Non Return to Zero). In the case of RLL (2, 10), arun length is limited so as to have a value ranging from 2 to 10. Therewritable optical disk of this example records data in the form of NRZI(Non Return to Zero Inverted), and therefore, in other words, in thecase of RLL (2, 10), it can be said that lengths of a mark and a spaceare limited in a range from the minimum length 3T (two zeros) to themaximum length 11T (10 zeros). In the case of this example, 3T isreferred to as a shortest mark T_(min) and 11T is referred to as alongest mark T_(max).

Among the fields constituting the data recording field 1003, the gapfield 1006 is an field formed as a time margin for post-processing forreproducing address information from the header field 1002 of theapparatus and pre-processing for recording data in the subsequent fieldsbelow the front guard field 1007, but data to be reproduced is notrecorded herein. The front guard field 1007 and rear guard field 1012fieldreas for absorbing deterioration of a recording film that occurswhen repeatedly recording data in the same sector, in which a specificrepetitive pattern is recorded. The data VFO field 1008 is for recordinga single pit pattern for quickly performing the lead-in operation of areproductive-system PLL when reproducing data. In the case of thisexample, a continuous pattern of 4T-mark·4T-space same as the case ofeach VFO field of the header field 1002 is recorded in the front guardfield 1007, data VFO field 1008, and rear guard field 1012.

The pre-sync code field 1009 records a pre-sync which is a specificpattern provided to detect the head of the succeeding data field 1010and easily make bits synchronization. The data field 1010 is an fieldfor actually recording user data, which is constituted of a plurality ofsync frames in order to secure reliability of bite synchronizationthough not illustrated, and a sync code serving as a specific pattern isadded to the head of each sync frame to facilitate the bitesynchronization in each sync frame. Moreover, an error detection codeaccording to a predetermined code rule is added to the user datarecorded in the data field 1010 and the user data is recorded after theuser data is modulated by using an 8/16RLL(2, 10) modulation code sameas that used for each address information field (PID) and each errordetection code field (IED) of the header field 1002. The data postamblefield 1011 records a specific pattern showing the end of the data field1010. The buffer field 1013 is an field for a time margin provided so asnot to overwrite a header field immediately after even if a linearvelocity is changed due to a factor such as rotational fluctuation oreccentricity of a disk when recording data, but data is not recorded inthe field 1013.

Then, a method is described below which is used for a conventionaloptical disk drive when recording/reproducing data in or from arewritable optical disk having a sector structure of a data format asdescribed above.

In the case of a conventional optical disk drive, whenrecording/reproducing data in or from a predetermined sector 1001, theposition of the predetermined sector 1001 on a disk is first specifiedby identifying address information from the header field 1002 togenerate a timing for actual recording or reproducing in the datarecording field 1003 after the above error detecting circuit detectsthat a pattern of the address information to which an error detectioncode is added, that is, (address information+error detection code) doesnot includes an error.

Moreover, in the case of the conventional optical disk drive, to recorddata in the predetermined sector 1001, it is a condition for recordingdata in the sector 1001 that there is no error inaddress-information-error-detection coded data in at least an addressfield, that is, at least a pattern of (address information+errordetection code). That is, when there is an error in the pattern of(address information+error detection code) in every address field of asector in which data will be recorded, the sector is judged as adefective sector and data is not recorded in the sector but theprocessing for substitution-recording data in another sector instead ofthe defective sector is performed.

Moreover, in the case where there is an error in the pattern of (addressinformation+error detection code) in every address field of thepredetermined sector 1001 when reproducing data from the sector 1001, itis impossible to correct a sector sync counter in the sector andtherefore, by using an output of a sector sync counter corrected by asector having at least one address field in which an error is notdetected in the pattern of (address information+error detection code)immediately before the sector 1001, the timing necessary for reproducingthe data of the sector is interpolated and reproduced.

As described above, the conventional optical disk drive cannot executerecording when there is an error in every address field of a sector towhich data will be recorded. Therefore, the substitution processing ofrecording the data to be recorded to another sector must be executed,and a problem occurs that a lot of processing time is necessary and therecording throughput lowers. Particularly, when the data continuouslyinput such as AV data is recorded to an optical disk, a fatal problemmay occur that data is lost or recording must be interrupted because thedata-recording speed cannot be ready because of the substitutionprocessing due to an error in an address field.

Moreover, the conventional optical disk drive corrects a sector synccounter at the timing at which it is detected that there is no error inat least one address field of each sector and generates the timingrequired to record or reproduce data, and therefore it is necessary togenerate a timing by interpolating the timing obtained from a sector inwhich there is no error in an address field immediately before in thecase where there is an error in every address field of a sector fromwhich data will be reproduced. Therefore, a problem lies in the accuracyof the data-reproducing timing. Particularly, when sectors having anerror in every address field continuously occurs, a shift occurs in atiming signal necessary for detecting the first of data such as theabove pre-sync detection window signal and there is a danger that apattern may not be detected or may be erroneously detected. Moreover, inthe worst case, a fatal problem may occur that a plurality of frames atthe head of a sector are lost and thereby, a data error cannot becorrected and data cannot be reproduced.

Moreover, in the case of an information recording system for recordinginformation in an optical disk having the data format shown in FIG. 18by combining the optical disk drive with a host computer, field1-timecharacteristic, that is, a predetermined transfer rate is generallyrequested for the operation for recording AV data in the optical disk.However, the real-time characteristic is not always requested for theoperation for recording computer data to be handled by a conventionalpersonal computer in an optical disk but occurrence of an error is notpermitted because even a small data error in computer data may give afatal influence to a system.

In the case of the information recording system for recording theinformation including AV data having the real-time characteristic andthe computer data which cannot permit an error in an optical disk, it isassumed that data errors include two types such as a data error and anaddress-information error.

For the data error, the idea of assuring the quality of recorded data byverifying the data is applied in the case of a conventional apparatus,however, in performing verification, a problem occurs that thenormal-recording-sequence execution time increases.

For the address-information error, data is not recorded to a sector inwhich errors equal to or more than a predetermined number of errors aredetected in address information in the conventional apparatus. Moreover,the data is generally recorded to the sector through retrying process.However, the recording-sequence execution time is increased due toretrying of recording to the same sector or alternation recordingprocessing, a problem occurs that a data transfer rate for recording isdeteriorated.

DISCLOSURE OF THE INVENTION

The present invention is made to solve the above problems and its objectis to provide an optical-disk recording and/or reproducing apparatus forrecording and/or reproducing data at a high reliability by minimizingdeterioration of the recording throughput even if an error rate in anaddress field of a sector is lowered, and also to provide an informationrecording system and an information recording method employing the aboveapparatus and method.

To achieve the above object, an optical-disk recording and/orreproducing apparatus of the present invention is an optical-diskrecording apparatus for recording data in a data recording field of anoptical disk having a sector structure constituted of a header fieldpreviously storing address information and a data recording field forstoring data, in which the header field includes an address mark fieldstoring an address mark showing a beginning of address information, anaddress information field storing address information, and an errordetection code field storing an error detection code for detecting anerror in the address information field, said apparatus comprising:

means for detecting an address mark stored in the address mark field ofthe sector; and

means for deciding and controlling a period of recording and/orreproducing data in and/or from the data recording field of the sector,wherein said data-recording and/or reproducing decision and controlmeans uses an address-mark detection timing of the address-markdetection means in the decision and control of the data recording and/orreproducing period.

In the above optical-disk recording and/or reproducing apparatus, thedata recording and/or reproducing decision and control means includes:address-information error detection means for detecting presence orabsence of an error in the address-information based on the addressinformation and the error detection code; and timing generation meansfor generating a recording and/or reproducing timing signal for decidinga data recording and/or reproducing operation by using the timing ofdetecting the address mark by the address-mark detection means and thetiming of detecting by the address-information error detection meansthat there is no error in the address information.

In the above configuration, the data recording and/or reproducingdecision control means permits recording and/or reproducing of data onlyin the following two cases when recording and or reproducing data inand/or from the data recording field of a predetermined sector:

(case 1) where address information having no error is obtained as aresult of error detection in the subject sector executed by theaddress-information error detection means, and

(case 2) where at least one piece of address information having no erroris obtained in a predetermined number of sectors preceding the subjectsector as a result of error detection by the address-information-errordetection means and at least one address mark is detected in the addressmark field of the subject sector.

Moreover, an optical-disk recording and/or reproducing method of thepresent invention is an optical-disk recording and/or reproducing methodfor recording data in a data recording field of an optical disk having asector structure constituted of a header field previously storingaddress information and a data recording field for storing data, inwhich the header field includes an address mark field storing an addressmark showing a beginning of address information, an address informationfield storing address information, and an error detection code fieldstoring an error detection code for detecting an error in the addressinformation field, the method comprising the steps of:

detecting an address mark stored in the address mark field of thesector; and

deciding and controlling a period of recording and/or reproducing datain and/or from the data recording field of the sector, wherein theaddress-mark detection timing is used in the decision and control of thedata recording and/or reproducing period.

In the above optical-disk recording and/or reproducing method, thedata-recording decision and control step includes: anaddress-information error detecting step of detecting presence orabsence of an error in the address-information based on the addressinformation and the error detection code; and a timing generation stepof generating a recording and/or reproducing timing signal for decidinga data recording and/or reproducing operation by using the address markdetection timing and the timing of detecting that there is no error inthe address information.

Moreover, an information recording system of the present invention is aninformation recording system for recording information includingtransfer-rate-priority data and transfer-rate-nonpriority data inmixture supplied from an external unit to an optical disk having asector structure constituted of a header field previously storingaddress information and a data recording field for storing data, saidsystem comprising:

an optical disk drive for recording data to the data recording field ina predetermined sector of the optical disk; and

determination means for determining whether the information to berecorded to the optical disk is transfer-rate-priority data ortransfer-rate-nonpriority data,

wherein when the information is the transfer-rate-priority data, theoptical disk drive records the information in the sector to record thedata even if there are errors equal to or more than a predeterminedcriterion in address information in the sector to record the data, andwhen the data is the transfer-rate-nonpriority data, the optical diskdrive performs a recording retry process if there are errors equal to ormore than the predetermined criterion in the subject sector.

In the above information recording system, the data determination meansdetermines whether the information is transfer-rate-priority data ortransfer-rate-nonpriority data by interpreting whether a command is acommand for handling the transfer-rate-priority data or a command forhandling the transfer-rate-nonpriority data issued from an external unitto the optical disk drive.

Moreover, an information recording method of the present invention is aninformation recording method for recording data supplied from anexternal unit to a data recording field of an optical disk having asector structure constituted of a header field previously storingaddress information and a data recording field for storing data, themethod comprising:

a step of determining whether the information to be recorded to theoptical disk is transfer-rate-priority data or not, and

a control step of recording the data in the sector to record the dataeven if there are errors equal to or more than a predetermined criterionin address information in the sector to record the data in the case ofthe transfer-rate-priority data, and recording the data in a substitutesector without recording the data in the subject sector to record thedata if there are errors equal to or more than the predeterminedcriterion in the subject sector in case of the transfer-rate-nonprioritydata.

The above information recording method further comprises a step ofdetecting an address mark recorded in an address mark field of thesubject sector, and a step of deciding and controlling a period ofrecording data to the data recording field of the subject sector,wherein the address-mark detection timing is used for decision andcontrol of the data recording period.

The data-recording decision and control step includes: anaddress-information error detecting step of detecting presence orabsence of an error in the address-information based on the addressinformation and the error detection code; and a timing generation stepof generating a recording timing signal for deciding a data recordingoperation by using the address mark detection timing and the timingdetected in the address-information error detecting step of detectingthat there is no error in the address information.

According to the configuration of an optical-disk recording apparatus oran optical-disk reproducing apparatus of the present invention, it ispossible to decide data-recording start timing or data-reproducing starttiming in accordance with the address mark detection timing, andtherefore, it is possible to accurately record or reproduce data in orfrom a sector even including errors in address information, and therebyimprove the reliability of the apparatus.

Moreover, according to the configuration of an optical-disk recordingapparatus or an optical-disk reproducing apparatus of the presentinvention, it is possible to determine whether data recording or datareproducing is performed to or from a predetermined sector under thecondition that, when address information having no error is obtained inthe subject sector, or when address information having no error isobtained in at least a certain sector in a predetermined sectorspreceding the subject sector together with an address mark beingdetected in the subject sector. Therefore, by correcting a sector synctiming in the sector concerned, it is possible to improve thereliability of the apparatus because data is recorded or reproduced inor from only a sector in which an accurate timing can be generated.

Furthermore, according to an optical-disk recording method of thepresent invention, it is determined whether the data is transfer-ratepreference data or error-permissive data and data recording of only thetransfer-rate-preference data is executed, and therefore it is possibleto minutely correspond to an apparatus performance requested for eachdata.

Thus, by applying an optical-disk recording method of the presentinvention to an information recording system for handling multimediaincluding computer data and real-time AV data in mixture, it is possibleto provide a high-speed and high-reliability system.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram showing a configuration of an optical diskdrive according to the present invention;

FIG. 2 is an illustration showing a configuration of a data format in asector of an optical disk according to the present invention;

FIG. 3 is a block diagram showing a configuration example of an internalstructure of timing generation means 114 and a periphery thereof in oneembodiment of the present invention;

FIGS. 4(a), (b), (c), (d) and (e) are timing charts for explaining anexample of a counted-value correcting operation of a sector sync counter202 in one embodiment of the present invention;

FIGS. 5(a), (b), (c), (d) and (e) are timing charts for explaininganother example of a counted-value correcting operation of the sectorsync counter 202 in one embodiment of the present invention;

FIGS. 6(a), (b), (c), (d) and (e) are timing charts for explaining anexample of a counted-value correcting operation of the sector synccounter 202 in one embodiment of the present invention;

FIGS. 7(a), (b), (c), (d), (e) and (f) are timing charts for explainingoperations of a counted-value decoding means 203 in one embodiment ofthe present invention;

FIG. 8 is a block diagram showing a configuration example of an internalstructure of timing generation means 114 and a periphery thereof in oneembodiment of the present invention;

FIGS. 9(a), (b) and (c) are timing charts for explaining operations ofcounted-value decoding means 303 in one embodiment of the presentinvention;

FIG. 10 is a block diagram showing a configuration example of aninternal structure of timing generation means 114 and a peripherythereof in one embodiment of the present invention;

FIGS. 11(a), (b), (c), (d), (e), (f), (g), (h)) and (i) are timingcharts for explaining an example of a counted-value correcting operationof a sector sync counter 402 in one embodiment of the present invention;

FIG. 12 is a flowchart for explaining a data recording/reproducingprocess in one embodiment of the present invention;

FIG. 13 is a block diagram showing a configuration example of aninformation: recording system according to the present invention;

FIG. 14 is a flowchart for explaining a data recording process in oneembodiment of the present invention;

FIG. 15 is a flowchart for explaining a data recording process in oneembodiment of the present invention;

FIG. 16 is a flowchart for explaining a data determination process inone embodiment of the present invention;

FIG. 17 is a flowchart for explaining a data recording process in oneembodiment of the present invention; and

FIG. 18 is an illustration showing a configuration example of a dataformat in a sector of a conventional optical disk.

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiments of the present invention are described below by referring tothe drawings.

FIG. 1 is a block diagram showing a configuration of an optical diskdrive (also referred to as disk drive) according to the presentinvention. In FIG. 1, a disk motor 102 rotates an optical disk 101 at apredetermined revolution number. An optical pickup 103 includes asemiconductor laser, optical system, and photodetector to record andreproduce data when a laser beam emitted from the semiconductor laser iscondensed by the optical system to apply a light spot to the recordingface of the optical disk 101. Moreover, the light reflected from therecording face is condensed by the optical system, converted to acurrent by the photodetector, and moreover voltage-converted andamplified by an amplifier 104, and outputted as a reproduced signal.

A servo circuit 105 performs a rotation control of the disk motor 102,transfer control for moving the optical pickup 103 in a radius directionof the optical disk 101, focus control for focusing a light spot on adisk recording face, and tracking control for tracking a light spot tothe center of a target track. For the focus control and trackingcontrol, a focus error signal and a tracking error signal are used amongreproduction signals serving as outputs of the amplifier 104. The focuserror signal is an electrical signal showing a defocus of a light spotfrom the recording face of the optical disk 101 and the tracking errorsignal is an electrical signal showing a shift of a light spot from apredetermined track of the optical disk 101.

A reproduction-signal processing section 106 fetches a signal componentcorresponding to the data recorded in the optical disk 101 from areproduction signal, binarizes the fetched signal to binary data,generates a read clock in accordance with the binary data and areference clock, by a built-in PLL (Phase Locked Loop) (notillustrated), and reproduces read data synchronizing with the readclock.

A laser driving section 108 generates a laser-driving signal so that asemiconductor laser built in the optical pickup 103 emits light by areproduction power when reproducing an address and user data, and by arecording power when recording data.

A format encoder/decoder 107 reproduces the address information that isrecorded in the optical disk 101 in accordance with the read clock andread data output from the reproduction signal processing section 106,and generates and supplies various timing signals necessary forrecording or reproducing at the timing synchronized with a sector of theoptical disk 101 on the basis of the position of the reproduced addressinformation. It is possible to record or reproduce data at a correcttiming by outputting a timing signal such as read gate signal which isnecessary for binarization of an address or data or PLL processing tothe reproduction signal processing section 106 at the time ofreproduction, or by outputting a timing signal such as a write gatesignal for allowing light emission of a recording power to the laserdriving section 108 at the time of recording.

Portions relating to the present invention among main functional blocksbuilt in the format encoder/decoder 107 are briefly described below.

An address-mark detection section 111 detects an address mark (AM) whichis recorded in an address field by using the read clock and read datasupplied from the reproduction signal processing section 106. Ademodulation section 112 demodulates address information and user databy using the read clock and read data supplied from the reproductionsignal processing section 106. An address-error detection section 113detects errors in the address information (address demodulation data)demodulated by the demodulation section 112. A timing generation section114 secures the synch with a sector format by using an address-markdetection timing signal by the address-mark detection section 111 and atiming signal detecting that there is no error in address information bythe address-error detection section 113, and generates a timing signalnecessary for recording or reproducing data. Details of operations ofthe sections above described will be described later.

Moreover, when recording data, the format encoder/decoder 107 adds aredundant data parity such as an error correction code to user datasupplied from an external unit through a host interface 109, and outputswrite data modulated by a built-in modulation section 115 in accordancewith a predetermined format to the laser driving section 108. Moreover,when reproducing data, the format encoder/decoder 107 performsdemodulation and error correction of the data recorded in the opticaldisk 101 in accordance with the read clock and read data output from thereproduction signal processing section 106, and transmits the correcteddata to an external unit through the host interface 109.

A system controller 110 interprets a command supplied from an externalunit through the host interface 109 to control operations of the servocircuit 105, reproduction signal processing section 106, formatencoder/decoder 107, laser driving section 108, and host interface 109so that data is recorded or reproduced in or from a predetermined sectorof the optical disk 101.

Hereafter, configurations and operations of the timing generationsection 114 and its periphery to be a specific feature of the presentinvention are described by using a plurality of examples.

In this case, it is assumed that the optical disk 101 in or from whichdata will be recorded or reproduced has the data format shown in FIG. 2as an example of a sector format. Moreover, a case is described as anexample in which a predetermined number of bites shown in FIG. 2 isassigned to each field of the data format shown in FIG. 18 described forthe prior art. Furthermore, one byte denotes a length of 8 bits in thecase of binary data, namely, a length of 16 channel bits in the case ofa modulated pattern. In the case of this example, the length of onesector is equal to 2,697 bytes in which the length of the header field1002 uses 130 bytes.

A parameter J used to show lengths of the gap field 1006 and bufferfield 1013 is an integer ranging from 0 to 15 and the total number ofbytes of the gap field and buffer field becomes 35 (constant value).Moreover, a parameter K used to show lengths of the front guard field1007 and rear guard field 1012 is an integer ranging from 0 to 7. Theseparameters J and K are selected at random at the apparatus side.Thereby, recording start and end positions and the recording position ofa specific pattern of such as a sync code are not fixed in apredetermined sector and thus, it is possible to reduce thedeterioration of a recording film that occurs when data is repeatedlyrecorded.

In this case, a specific pattern{000100010000000000000100010001000000000000010001} having a length of 3bytes (that is, 48 channel bits) is recorded in each address mark field(AM) of each address field section. This is an NRZI notation comprising{4T-mark·4T-space·14T-mark·4T-space·4T-mark·14T-space·4T-mark}. Becauseone 14T-mark and one 14T-space each having a length of (T_(max)+3T) arerespectively included, a code distance is long and thereby, theprobability of erroneously detecting the pattern of the addressinformation field PID, error detection code field IED, and data field1010 for which 8/16RLL(2, 10) is used as a modulation code, for theabove address mark, is low. Moreover, because the DSV of an address markhas a small value of 4, it is possible to stably keep a slice level whena reproduction system of an apparatus binarizes an address mark andsubsequent address information field and error detection field. In thiscase, DSV is the abbreviation of Digital Sum Value, which is obtained byassuming encoding data 1 as +1 and encoding data 0 as −1 and therebycalculating the total sum in a certain pattern and used as a scale formeasuring an influence on a reproduction system for binarization or thelike in order to show the DC component of a code word.

First, the basic operation is described below of generating a timingsignal for actually recording or reproducing in the data recording field1003 in accordance with the timing of detecting that there is no errorin the pattern of address information (address information+errordetection code) by the address-error detection section 113. The aboveoperation is performed, similarly to the prior art, by using a counterfor counting a clock having a one-channel-bit cycle or a cycle ofintegral multiples of the one-channel-bit cycle.

More specifically, the above counter is a sector sync counter forcounting a one-sector length of 2,697 bytes and a count value iscorrected to a predetermined counted value at the timing at which anerror detection circuit detects that there is no error. Because the dataformat shown in FIG. 2 has a plurality of address fields, the countvalue is corrected to a respective counted value when the address fieldnumber in order in a sector can be identified in accordance with theadditional information included in the address information. Bycorrecting a counted value including the time required to identify anaddress field in the number of bytes of end positions of the first tofourth address fields 1004a, 1004b, 1004c, and 1004d from the head of asector, the counted value serving as an output of the sector synccounter can almost accurately express a byte position from the head ofthe sector. Therefore, by using the output of the sector sync counter,it is possible to generate the recording/reproduction start timings of asector to be recorded/reproduced.

For example, it is assumed to generate a recording-gate signal whichbecomes H-level in the period from the front guard field 1007 up to therear guard field 1012 of a sector to be recorded, for use in therecording-operation control of the recording system of an apparatus. Inthe case of the data format of this example, the start position of thefront guard field 1007 is (140+J/16) bytes behind the head of the sectorand the end position of the rear guard field 1012 is (2672+J/16).Therefore, when assuming that a clock having a cycle of one channel bitis used, it is possible to generate the above recording-gate signal byusing a logic circuit in which the recording-gate signal is set to Hlevel when a counted value of the sector sync counter indicates(140+J/16) in terms of the number of bytes, that is, 16 times (2,240+J)of the (140+J/16) in terms of the number of channel bits and the signalis set to L level when the counted value of the sector sync counterindicates (2,672+J/16) in terms of the number of bytes, that is, 16times (4,2752+J) of the (2,672+J/16) in terms of the number of channelbits. Practically, because the recording-gate signal is early set to Hlevel in consideration of such as a circuit delay of the recordingsystem, an offset value may be provided to the above counted value.

As another example, it is assumed to generate a pre-sync detectionwindow signal which is to be set to H level in at least thepre-sync-code field 1009 of a sector having data to be reproduced andwhich is used for pre-sync detection of an apparatus. In the case of thedata format of this example, the end position of the pre-sync-code field1009 is (198+K+J/16) bytes behind the head of the sector. Therefore, todetect a pre-sync through the complete coincidence detection ofthree-byte pattern so that the pre-sync can be detected while apre-sync-detection-window signal is kept H-level even if J and Krespectively take any value, it is necessary to generate apre-sync-detection-window signal to be kept H-level in the period fromat least 198 bytes later from the head of the sector up to (205+15/16)bytes later for which the maximum value 7 of K and the maximum value 15of J are substituted. Practically, the time position of a pre-syncdetection window may be shifted by considering a processing delay suchas a circuit delay of a reproduction system or an H-level period may beset widely to a certain extent by considering a fluctuation factor suchas a linear velocity. Because not only detection of a pre-sync is usedbut also it is used together with detection of the sync code of thefirst frame of the data field 1010, the end position of H level may beset to be delayed by a predetermined number of bytes. Moreover, when apre-sync is detected not through complete coincidence detection ofthree-byte pattern but through detection of only partial coincidence, itis also permitted to set the H-level period of the pre-sync detectionwindow to a width other than the above described.

(Embodiment 1)

FIG. 3 is a block diagram showing a configuration of a timing generationsection 114 and a configuration of the periphery thereof in anembodiment of the present invention and operations thereof are describedbelow in detail by referring to FIG. 3.

First, an address-mark detection section 111 detects a pattern of anaddress mark recorded in each address mark field (AM) shown in FIG. 2 byusing a read clock RCLK and read data RD supplied from the reproductionsignal processing section 106 and outputs an AM detection pulse AMDP atthe timing of detecting the address mark.

A demodulation section 112 demodulatesaddress-information-error-detecting-and-encoding data corresponding toaddress information and an error detection code recorded in an addressinformation field (PID) and an error detection code field (IED),respectively, that is, (address information+error detection code) byusing the read clock RCLK and read data RD, and generates and outputsaddress demodulation data ADMD. When generating the address demodulationdata ADMD corresponding to (address information+error detection code),the demodulation section 112 refers to the AM detection pulse AMDP asthe timing for generating the demodulation data ADMD and startsdemodulation by using read data RD corresponding to the following(address information+error detection code) in accordance with the timingof the AM detection pulse AMDP.

An address-error detection section 113 detects whether there is an errorin the pattern of (address information+error detection code) by usingthe address demodulation data ADMD. When there is no error, the section113 outputs a CRCOK pulse (CRCOK). According to the example of the dataformat in FIG. 2, (address information+error detection code) data iscomprised of 6 bytes in total and it is assumed that an error detectioncode of 2 bytes out of 6 bytes is encoded by using a known Reed-Solomoncode, it is possible to easily detect whether there is an error in thedata of the total 6 bytes by performing the known syndrome calculation.

The timing generation section 114 in FIG. 3 has a function of generatinga timing signal such as read gate signal WGS required to record data andis constituted of a reference-dock generation section 201, sector synccounter 202, counted-value decoder 203, and counted-value correctionsection 204. Each functional block is described below.

The reference-clock generation section 201 generates a reference dockREFCLK serving as a criterion for recording data. In this embodiment, itis assumed that one cycle of the reference clock is equal toone-channel-bit cycle of the data format shown in FIG. 17. To generatethe reference clock REFCLK by the reference-clock generation section201, a plurality of methods are considered in accordance with the trackformat of an optical disk 101. Moreover, because the reference clock isused to record data, the jitter component of the clock may influence therecording quality. Therefore, it is necessary to control the jittercomponent of the reference clock REFCLK so that the recording quality isnot deteriorated.

First, in the case of recording data over the whole circumferentialtracks at a fixed frequency as the known CAV (Constant Angular Velocity)system, it is permitted to generate clocks at a fixed frequency by usinga quartz oscillator. Moreover, in the case of such as the known ZCAV(Zoned Constant Angular Velocity) system to classify into zones everypredetermined radial range and change a recording frequency every zone,it is permitted to generate clocks at fixed frequencies different everyzone by using such as a frequency synthesizer. Moreover, as a certaintype of an optical disk, a pattern for obtaining a recording frequencymay be previously recorded on a disk. For example, the wobble groovesystem in which a guide groove for forming a track is meandered at apredetermined cycle and a sample servo system in whichclock-reproduction pits are formed every certain interval of trackscorrespond to the above systems. In this case, the reference-clockgeneration means 201 requires means for reproducing a pattern formed onan optical disk and PLL means for generating clocks synchronizing withthe reproduced pattern.

The sector sync counter 202 is a counter for counting the referenceclocks REFCLK so that a counted value of the counter 202 shows a byteposition in one sector. According to the data format shown in FIG. 2,one sector has a length of 2,697 bytes, that is, a length of2,697×1.6=43,152 channel bits. Therefore, when assuming that a referenceclock REFCLK is a clock having a cycle of 1 channel bit, it is possibleto constitute the counter 202 of a 16-bit loop counter which counts from0 to 43,151 and then returns to 0.

Moreover, it is necessary to synchronize the position of a light spot tobe applied to the optical disk with a counted value of the sector synccounter 202. Therefore, employed is a technique that the counted valueis corrected by using a counted-value correction pulse CCP and countcorrection value CCV output from the counted-value correction section204. The function of the counted-value correction means will bedescribed later. In this embodiment, a counted value of the sector synccounter 202 is output as a counter output CT0 by assuming that thecounted value shows the number of channel bits from the head of eachsector.

The counted-value decoder 203 generates various timing signalssynchronizing with the data format of a sector by decoding the counteroutput CT0 output from the sector sync counter 202.

The example in FIG. 2 shows a case in which a data-recording commandRECCOM input through the host interface 109 is received from the systemcontroller 110, and the counted-value decoder 203 outputs a write gatesignal WGS to the laser driving section 108 and outputs an enable signalENBL necessary for demodulation to the demodulation section 115. Detailsof the timing-signal generation will be described later.

The counted-value correction section 204 receives an address-markdetection pulse AMDP output from the address-mark detection section 111and a CRCOK pulse showing that there is no error output from theaddress-error detection section 113, and outputs a counted-valuecorrection pulse CCP and a count correction value CCV to the sector synccounter 202.

FIGS. 4 show the timings for explaining the counted-value-correctingoperation of the sector sync counter 202 in this embodiment. The top ofFIG. 4 shows details of the data format of the header field 1002 in onesector, in other words, a position to which a light spot follows in apredetermined sector on an optical disk. Moreover, it is assumed thattime advances from left to right.

In the case of the address-mark detection pulse AMDP output from theaddress-mark detection section 111, a pulsatile H level is output at thetiming of detecting an address mark by reproducing each address markfield (AM). Therefore, the pulse AMDP is output to be delayed by thetime equivalent to the number of delay channel bits of approx. n1 laterthan the following position of a light spot (each address-mark AM endposition) as AMDP-a, AMDP-b, AMDP-c, and AMDP-d as shown in Figure.Herein, n1 denotes the number of delay channel bits from the time when alight spot irradiates an address-mark terminal position up to the timewhen an AM detection pulse AMDP is output.

Referring to the CRCOK pulse output from the address-error detectionsection 113, a pulsatile H-level CRCOK is output when there is no erroras a result of demodulating reproduced data and detecting an error inaddress demodulation data by reproducing each address-information field(PID) and error detection field (IED). Therefore, as shown in Figure,the CRCOK pulse is output to be delayed by the time equivalent toapprox. n2 channel bits from the following position (each IED-sectionterminal position) of a light spot as OK-a, OK-b, OK-c, and OK-d.Herein, n2 denotes the number of delay channel bits from the time whenthe light spot irradiates an error-detection-IED-section terminalposition up to the time when the CRCOK pulse is output.

The counted-value correction pulse CCP is an H-level pulsatile signalgenerated by the counted-value correction section 204 by using the AMdetection pulse AMDP and CRCOK pulse. In this case, as shown in Figure,CCP-ma, CCP-mb, CCP-mc, and CCP-md are generated correspondingly toAMDP-a, AMDP-b, AMDP-c, and AMDP-d; and CCP-ea, CCP-eb, CCP-ec, andCCP-ed are generated correspondingly to OK-a, OK-b, OK-c, and OK-d,respectively; which are used for timings for correcting the countedvalues in the sector sync counter 202.

Count correction values CCV take values previously decided everypositions of the above AM detection pulse AMDP and CRCOK pulse. In thisembodiment, the values are set to A, B; C, D; E, F; and G, H in theaddress mark field AMa and error detection code field IEDa of firstaddress field 1004a, address mark field AMb and error detection codefield IEDb of second address field 1004b, address mark field AMc anderror detection code field IEDc of third address field 1004c, andaddress mark field AMd and error detection code field IEDd of fourthaddress field 1004d, respectively. Because the count correction valueCCV is output to the sector sync counter 202 together with thecounted-value correction pulse CCP, it must be decided at each H pulseportion of the counted-value correction pulse CCP.

To determine an address field in which the output AM detection pulseAMDP or CRCOK pulse is included, it is recommended to refer to, forexample, a bit pattern capable of specifying an order number of anaddress field to which the pulse AMDP or CRCOK corresponds. In general,since a code capable of identifying an address field number to which thepulse AMDP or CRCOK corresponds is assigned to a certain specific bit ofan address information field (PID), it is possible to easily identify byusing the bit.

Moreover, to determine an address field in which an address mark isincluded, it is permitted to use an identifiable pattern. However, thesame pattern is generally used for any address field. Therefore, it isnot easy to identify an address mark included in which address field.However, it is also possible to identify the address mark by referringto, e.g., a counted value of the sector sync counter 202 when theaddress mark is detected. Moreover, a method is considered whichidentifies an address mark by setting a specified detection window tothe address mark of each address field. This method will be describedlater in detail.

It is permitted to set the count correction values CCV for eachcounted-value correction pulse CCP, that is, values of A to H to thevalues as following, in order to completely synchronize a light-spotirradiation position with a value of a sector sync counter.

 A=39×16+n1+n3B=45×16+n2+n3C=57×16+n1+n3D=63×16+n2+n3E=103×16+n1+n3F=109×16+n2+n3G=121×16+n1+n3H=127×16+n2+n3

Herein, n3 denotes the number of delay channel bits from the time ofoutputting the AM detection pulse AMDP or CRCOK pulse up to the time ofcompleting correction of values counted by the sector synch counter 202.

Thus, by using the AM detection pulse AMDP serving as the address-markdetection timing and the CRCOK pulse serving as the timing of detectingno error in address information, it is possible to correct a countedvalue of the sector sync counter 202. Thereby, it is possible for thecounter output CT0 after the counted-value correcting operation toaccurately express the light-spot irradiation position at this point oftime, that is, the number of channel bits from the head of a sector.Therefore, it is possible to correct a positional shift of each sectorby correcting a counted value in the header field 1002 of the nextsector. Thus, even if a shift occurs between the counter output CT0 anda light-spot irradiation position when one sector is completed due to afluctuation factor such as the fluctuation of a linear velocity or thefluctuation of a reference-clock frequency due to a shift of the numberof revolutions or the eccentricity of a disk, it is possible to correctevery sector positional shift by correcting a counted value based on theheader field 1002 of the next sector to thereby accurately adjust thedata-recording/reproducing timing and keep a high reliability of anapparatus.

As described in the above embodiment, it is a feature of the presentinvention to correct a count value of the sector sync counter 202 byusing the AM detection pulse AMDP serving as the address mark detectingtiming. Thus, as described below, the present invention can effectivelyfunction even if an error is detected in every pattern of (addressinformation+error detection code) in a certain sector.

FIGS. 5 are timing charts for explaining a second example of thecounted-value-correcting operation of the sector sync counter 202 inthis embodiment. The example in FIG. 5 is different from the example inFIG. 4 in that an error is detected in every (address information+errordetection code).

In FIGS. 5, symbols ◯ and X drown immediately below the uppermost dataformat of the header field 1002 show that address marks field11 detectedin the address mark fields AMa, AMb, AMc, and AMd and errors aredetected in all of the error detection code fields IEDa, IEDb, IEDc, andIEDd. Therefore, the AM detection pulse AMDP is output after n1-channelbits period of a predetermined time from each address-mark sectionterminal similarly to the example in FIG. 4. Moreover, no H pulse of theCRCOK pulse is output in the illustrated sector but the CRCOK pulse iskept L-level (shown by a dotted line) differently from the example ofFIG. 4.

Therefore, the counted-value correction pulse CCP is output as an Hpulse only when the pulse CCP corresponds to the time when the AMdetection pulse AMDP is output. The count correction value CCV has apredetermined value every position of the output AM detection pulseAMDP. That is, the value CCV becomes A, C, E, and G in the address markfields AMa, AMb, AMc, and AMd, respectively.

A conventional method cannot correct the timing in a sector having anerror in every address information. Therefore, if a shift occurs betweenthe counter output CT0 and a light-spot irradiation position when onesector is completed due to a fluctuation factor such as the fluctuationof a linear velocity of the fluctuation of a reference-clock frequencydue to a shift of the number of revolutions or eccentricity of a disk,the influence of the shift may reach up to the next sector. Moreover, ifsectors having an error in every piece of address informationcontinuously occurs, the data-recording/reproducing timing is greatlyshifted because shifts fieldccumulated. In the worst case, a trouble mayoccur that data is recorded up to a position in which data must notoriginally be recorded or recorded data cannot correctly be reproduced.However, this embodiment exhibits the following advantage for the aboveconventional problem.

That is, according to the configuration shown in this embodiment, whenonly an address mark is detected even in a sector having an error inevery piece of address information, it is possible to correct a countedvalue of the sector sync counter 202 by using the AM detection pulseAMDP. Therefore, it is possible to correct a shift in position for eachsector independently of an error existence or absence in the addressinformation, and accurately adjust the datarecording/reproducing timing,and keep the high reliability of an apparatus.

FIGS. 6 are illustrations for explaining a third example of thecounted-value-correcting operation of the sector sync counter 202 inthis embodiment. The operation example in FIG. 6 is characterized inthat counted-value correction according to the address-mark-detectiontiming is not performed after counted-value correction following a CRCOKpulse is once performed as described below.

In FIG. 6, symbols ◯ and X drawn immediately below the uppermost detailsof the data format of the header field 1002 show that address marks aredetected (◯) in all of the address mark fields AMa, AMb, AMc, and AMdand errors (X) are detected in error detection code fields IEDa and IEDbbut an error is not detected (◯) in error detection code fields IEDc orIEDd. Therefore, the AM detection pulse AMDP is output as an H pulse atfour places (shown by AMDP-a, AMDP-b, AMDP-c, AMDP-d) similarly to theexample in FIG. 5. Moreover, the CRCOK pulse is output as an H pulse atonly two latter-half places (shown by OK-c, OK-d) in the illustratedsector differently from the example in FIG. 5.

The counted-value correction pulse CCP is output as an H pulse at thetotal of five places such as timings (shown by CCP-ma, CCP-mb, andCCP-mc) of the AM detection pulses AMDP at three places corresponding tothe address mark fields AMa, AMb, and AMc and timings (shown by CCP-ecand CCP-ed) of the CRCOK pulses at two places corresponding to the errordetection code fields IEDc and IEDd. The count correction value CCVtakes a predetermined value shown in FIG. 4 for each position, that is,A, C, E, F, and H in the order from the front.

As shown in this example, if the CRCOK pulse is once output in eachsector (in this example, an OK-c pulse corresponding to IEDc isgenerated), the counted-value correction pulse CCP is not output at thetiming corresponding to the AM detection pulse AMDP. In this example,the counted-value correction pulse (illustrated by a dotted line)corresponding to AMd is not output. Therefore, in a sector in which itis detected that there is no error in at least one address field(address information+error detection code), it is possible tosynchronize the sector sync counter 202 on the basis of the timing ofthe CRCOK pulse without fail (shown by CCP-ec and CCP-ed in thisexample) and synchronize the sector sync counter 202 on the basis of thetiming of the AM detection pulse AMDP only in a sector in which only anaddress mark is detected.

In an optical disk having a data format of a header field including aplurality of address fields comprising at least (address markfield+address information field+error detection code field) in eachsector, every address mark generally has the same pattern, and thenumber of the address field including the address mark among a pluralityof ad dress fields can be determined by checking a specific bit of anaddress information field in many cases. When the above data format isused, it can be said that the CRCOK pulse has a reliability forspecifying a position higher than that of the AM detection pulse AMDP.From the above viewpoint, after correcting a counted value at the timingof detecting that there is no error in (address information+errordetection code) in each sector, it is possible to accurately adjust thedata recording/reproducing timing and keep the liability of an apparatushigh as this example by synchronizing with the timing of the CRCOK pulseas a criterion so as not to correct a counted value at the address-markdetection. timing.

FIG. 7 is a timing chart for explaining the timing-signal generatingoperation of the counted-value decoder 203 in this embodiment. When thecounted-value decoder 203 receives a recording command RECCOM whenrecording data as described above, it outputs a write gate signal WGS tothe laser driving section 108 and outputs various enable signals ENBLnecessary for modulation, that is, a VFO enable signal ENBLa, dataenable signal ENBLb, rear-guard enable signal EMBLc, and sync-codeenable signal ENBLd.

In FIG. 7, the write gate signal WGS is a gate signal for allowing thelaser driving section 108 to emit a recording laser power. By allowingthe; recording laser power to be emitted only when the write gate signalWGS is kept H-level and thereby inhibiting emission of a high laserpower at the time of reproduction (at the time of L level), it ispossible to prevent a careless recording operation from being performed.Moreover, the write enable signal WGS makes it possible to controlon/off of operations of a high-frequency module (not illustrated) builtin the laser driving section 108. That is, by superimposing a highfrequency on. a laser power only at the time of reproduction, it ispossible to reduce laser noises and improve the S/N ratio of areproduction signal. The counted-value decoder 203 keeps the write gatesignal WGS H-level while the counter output CT0 has a value of c1 to(c6−1) as shown in FIGS. 7(a) and 7(b) by decoding the counter outputCT0 supplied from the sector sync counter 202 in a sector to perform arecording. Thereby, it is possible to emit a recording laser power onlyin a range from c1 channel bit and c6 channel bit from the head of asector to perform a recording.

The VFO enable signal ENBLa shown in FIG. 7(c) is a timing signal forurging the modulation section 115 to output patterns corresponding tothe front guard field 1007 and data VFO field 1008. In the case of thedata format used in this embodiment, a continuous pattern of4T-mark·4T-space is recorded in the above fields. Therefore, themodulation section 115 operates so as to output the above patterns forthe total (55+K) bytes while the VFO enable signal ENBLa is keptH-level. The counted-value decoder 203 decodes the counter output CT0 ina sector for recording and keeps the VFO enable signal ENBLa H-levelwhile the counter output CT0 has a value of c2 to (c3−1).

The data enable signal ENBLb shown in FIG. 7(d) is a timing signal forurging the modulation section 115 to output modulation data patternscorresponding to the total 2,422 bytes of a pre-sync code field 1009,data field 1010, and data postamble field 1011. When the data enablesignal EMBLb becomes H-level, the modulation section 115 first outputspatterns of a pre-sync code of 3 bytes and then outputs the data oftotal 2,418 bytes from the data field corresponding to a sync frameconstituted of fieldr-sync code and modulated data, and finally outputspatterns of a data postamble of 1 byte. In the case of the data formatin this embodiment, one sync frame in the data field is constituted oftotal 93 bytes including 2 bytes of a sync code and 91 bytes ofmodulated data and twenty-six frames of 93-byte sync frames (that is,2,418 bytes) are output. The counted-value decoder 203 decodes thecounter output CT0 in a sector for recording and keeps the data enablesignal ENBLb H-level while the counter output CT0 has a value of c3 to(c4−1).

The sync-code enable signal ENBLd shown in FIG. 7(f) is used forcontrolling addition of a sync code, capture of pre-modulated data MPD,and data modulation. That is, the modulation section 115 operates so asto output a pattern corresponding to a sync code while the data enablesignal ENBLb and sync-code enable signal ENBLd are H-level, and tocapture and modulate the pre-modulated data and output a modulated-datapattern while the data enable signal ENBLb is H-level and the sync-codeenable signal ENBLD is L-level. The counted-value decoder 203 decodesthe counter output CT0 in a sector for recording and outputs H pulses ofthe sync-code enable signal ENBLd of 2 bytes from a counter output valueof (c3+93×16×S). In this case, S is an integer from 0 to 25. Therefore,an H pulse having a two-byte width is output 26 times which is equal tothe number of frames.

The rear guard enable signal ENBTc shown in FIG. 7(e) is a timing signalfor urging the modulation section 115 to output a pattern correspondingto the rear guard field 1012. In the case of the data format in thisembodiment, continuous patterns of 4T-mark·4T-space are recorded in therear guard field 1012. Therefore, the modulation section 115 operates soas to output the above patterns equivalent to (55-K) bytes while therear guard enable signal ENBLc is H-level. The counted-value decoder 203decodes the counter output CT0 in a sector for recording and therebykeeps the rear guard enable signal ENBLd H-level while the counteroutput CT0 has a value of c4 to (c5−1).

In this embodiment, although the VFO enable signal ENBLa is separatedfrom the rear guard enable signal ENBLd, according to the data format inthis embodiment, the modulation section 115 outputs the same patternwhen either of the signals is active, and therefore it is also permittedto use the signals as one common timing signal.

It is permitted to set decoded values corresponding to rise and fall ofthe timing signals, that is, values from c1 to c6 as shown below.c1=132×16c2=140×16+J−n4c3=(195+K)×16+J−n4c4=(2617+K)×16+J−n4c5=2672×16+J

In this case, n4 denotes the number of channel bits considering acircuit delay in the modulation section 115 and laser driving section108 and a delay time until a light spot is actually applied to therecording film of the optical disk 101. That is, by adding the offset ofn4 channel bits and generating the timing signals to the modulationsection 115, it is possible to offset a delay time up to irradiation ofthe light spot and thereby to accurately decide a recording position.

Moreover, as to c1, since a recording laser power is set beforerecording the data of the front guard field 1007, it is set to the 132ndbyte from the head of a sector in order to permit emission of a powerexceeding a recording or reproducing power in a predetermined region ofthe gap field 1006. In the case of an apparatus which does not requirethe above preparatory laser emission period immediately beforerecording, the value of c1 may be set so that a recording power can beemitted by the start end of the front guard field 1007.

Moreover, J and K are random parameters for controlling deterioration ofa recording film as described in the prior art. It is preferable to usemeans for selecting J and K at random every sector so that J is aninteger from 0 to 15 and K is an integer from 0 to 7.

(Embodiment 2)

FIG. 8 is a block diagram showing a configuration example of a timinggeneration section 114 for reproducing data and its periphery accordingto a second embodiment of the present invention. In FIG. 8, an addressmark detection section 111, demodulation section 112, and address errordetection section 113 have the same functions as those described inFIGS. 1 and 3, and therefore, descriptions thereof are omitted here.

The timing generation section 114 in FIG. 8 has a function of generatinga timing signal such as read gate signal RGS required to reproduce data.The timing generation section 114 is constituted of a reference-clockgeneration section 301, sector sync counter 302, counted-value decoder303, and counted-value (counter value) correction section 304. Each ofthese functional block is described below.

The reference-clock generation section 301 generates a reference clockREFCLK2 serving as a criterion for reproducing data. In this embodiment,it is assumed that one cycle of the reference clock is equal to4-channel-bit cycle of the data format shown in FIG. 2. As to a methodof generating the reference dock, a plurality of methods are considereddepending on the track format of an optical disk 101, which is similarto the case of describing the reference clock generation section in therecording operation shown in FIG. 3. Therefore, descriptions thereof isomitted here.

Moreover, in contrast to the case of recording, it is unnecessary togreatly suppress the jitter component of a clock because the jitter isnot related to a quality of recording data. Because a timing signalrequired to reproduce data is generated by using the reference clockREFCLK2, it is permitted to use a frequency corresponding to a linearvelocity. Therefore, it is permitted to use read clock RCLK output bythe reproduction signal processing section 106 also as the referenceclock REFCLK2.

The sector sync counter 302 is a counter for counting the referenceclock REFCLK2 so that a counted value of the counter 302 shows a byteposition in one sector. According to the data format shown in FIG. 2,one sector has a length of 2,697 bytes, that is, a length of2,697×16=43,152 channel bits. When assuming that the reference clockREFCLK2 is a clock having a four-channel-bit cycle, it is possible toconstitute the counter 302 of a 14-bit loop counter which counts from 0up to 10,787 and then returns to 0 because a clock cycle of2,697×16+4=10,788 corresponds to the length of one sector.

Moreover, it is necessary to synchronize the position of a light spotapplied to the optical disk 101 with a counted value of the sector synchcounter 302. Therefore, a mechanism is used which corrects a countedvalue by using a counted-value correction pulse CCP2 and a countcorrection value CCV2 output from the counted-value correction section304. The counted-value correction section 304 receives an AM detectionpulse AMDP from the address mark detection section 111 and a CRCOK pulsefrom the address error detection section 113 and outputs thecounted-value correction pulse CCP2 and count correction value CCV2 tothe sector sync counter 302.

Because the mechanism for counted-value correction can be realized by amethod same as that described in FIGS. 3 to 6 for recording data indetail, description of the mechanism is omitted here. In thisembodiment, it can be said that a counted value of a sector sync countershows the position from the head of each sector in a unit offour-channel bits, that is, in 0.25 bytes unit and the counted value isoutput to an external unit as a counter output CT02.

The counted-value decoder 303 generates various timing signalssynchronizing with the data format of a sector by decoding the counteroutput CT02 output from the sector sync counter 302. In this case, whenthe decoder 303 receives a reproduction command REPCOM from the systemcontroller 110 when reproducing data, it outputs fieldd gate signal RGSto the reproduction signal processing section 106 and moreover outputs awindow signal WNS necessary for detection of a pre-sync code anddemodulation of data to the demodulation section 112. Details ofgeneration of the timing signals are described below.

FIGS. 9A to 9C are timing chart for explaining the timing generatingoperation of the counted-value decoding section 303 in this embodiment.In FIG. 9, the read gate signal RGS serves as a gate signal for allowingthe reproduction-signal processing section 106 to binarize areproduction signal and perform the PLL operation synchronizing withbinarized data. By performing operations such as binarization and PLLonly when the read gate signal RGS is kept H-level, it is possible toprevent an unnecessary reproducing operation from being performed at aportion in which data is not recorded and the operations are effectivefor stabilization of read clock and reduction of power consumption. Thecounted-value decoder 303 decodes the output CT02 shown in FIG. 9(a) ina sector for reproducing data and thereby keeps the read gate signal RSGshown in FIG. 9(b) H-level while the counter output CT02 has a valuefrom c7 to (c10−1). Hereby, it is possible to perform binarization andPLL operation by the reproduction-signal processing section 106 in aperiod from c7 channel bit to c10 channel bit from the head of a sectorfor reproducing data.

The sync-detection window signal WNS shown in FIG. 9(c) is a windowsignal for allowing the demodulation means 112 to detect a pre-sync codepattern and/or a first-frame sync-code pattern in a data field. Bydetecting a pre-sync and a first frame sync only when thesync-detection-window signal WNS is kept H-level, it is possible todetect the sync code in a proper range and prevent the sync code frombeing erroneously detected or undetected.

The demodulation section 112 starts detection of patterns of a pre-synccode and a first-frame sync code when the sync-detection window signalWNS becomes H-level, and starts demodulation of data from the firstframe when either of the patterns is detected. Moreover, as to framesync detection from the second frame downward, it is assumed that thedemodulation section 112 generates a window for detecting a followingframe sync at the timing of detecting a pre-sync code or a fist-framesync code to detect a sync within the above window. Moreover, when aframe sync code is not detected in a certain frame, the section 112starts interpolation from the sync-detection timing immediately before.

Furthermore, when neither pattern of a pre-sync code nor pattern of afirst-frame sync code is detected while the sync-detection window signalWNS is H-level, the operation for detecting a pre-sync code andfirst-frame sync code is stopped, and the sync detection window of thesecond frame is generated at a predetermined timing such as the falltiming of the sync-detection window signal WNS to perform theinterpolation. It is needless to say that the data of each frame isdemodulated by using the sync detection timing or interpolated synctiming.

Thus, by using the sync-detection window signal WNS and controlling theoperation for detecting a pre-sync-code pattern and/or a first-framesync code in a data field and detecting and interpolating syncs fromeither of the above pattern detection timings downward, it is possibleto efficiently and stably secure frame sync and reproduce data at a highreliability. Particularly, in the case of the data format used in thisembodiment, because a recording position using the parameters J and K isshifted at random, the position of a pre-sync-code field, in otherwords, the start position of the first frame of data changes at randomin a range of 8 bytes. Therefore, it is very important to generate thesync-detection window signal WNS at a proper position by using thetiming generation section 114 having the above sector sync counter 302.

The decoded values corresponding to rise and fall of timing signals,that is, values from c7 to c10 may be set as below.c7=170×4c8=202×4−wc9=202×4+wc10=2619×4

In this case, w denotes a parameter for deciding the window width of thesync-detection window signal WNS and in the above case, the window widthbecomes 8w channel bits. In the case of the sector sync counter 302 inthis embodiment, because a counted value is expressed in a unit of 0.25bytes, parameters of c7 to c10 are expressed in the form of (number ofbytes×4).

Moreover, the rise position of the read gate signal RSG is set to aposition located by 170 bytes after the head of a sector depending onthe value of the above c7. This position corresponds to a position atwhich the read gate signal RSG rises and which is located 2 bytes afterthe front end of the data VFO field 1008 when a recording position isshifted rearmost, that is, when the parameter J is equal to 15 and theparameter K is equal to 7. Thereby, it is possible to start databinarization and PLL lead-in operation from the head of the data VFOfield 1008 to the utmost while avoiding the front guard field 1007 inwhich a signal may be deteriorated. Thus, it is possible to stably andquickly reproduce data. To inhibit the reproducing operation in thefront guard field 1007, a timing error permitted in the read gate signalRGS, that is, an permitted positional shift of the sector sync counter302 is two bytes.

Moreover, when a recording position is present at the center in a rangeof random shift depending on the values of the above c8 and c9, forexample, when J is equal to 0 and K is equal to 4, the pre-sync codefield 1009 is set so that the end position of the field 1009 is broughtto almost the center of the sync-detection window signal WNS. To make itpossible to detect a pre-sync code even if a recording position isbrought to any position in a random-shift range (8 bytes), it isnecessary to set w so that at least 8w is larger than 8×16. Moreover, itis preferable to set w to 20 or more in order to securely detect thefirst frame sync in the data field 1010 following the pre-sync codefield 1009 and provide a slight allowance to the sector sync counter302. When setting w to an excessively large value, erroneous detectionincreases because a window width becomes too large. Therefore, w is setto a proper value through an experiment or the like.

Moreover, the fall position of the read gate signal RSG is brought to aposition located by 2,619 bytes after the head of a sector depending onthe value of the above c10. This position corresponds to a position atwhich the read gate signal RSG falls and which is located by two bytesafter; the data postamble field 1011 when a recording position isshifted foremost, that is, when the parameter J is equal to 0 and theparameter K is equal to 0. Thereby, it is possible to securely reproducethe data up to the data postamble field 1011 even if the recordingposition is brought to any position in the random shift range (8 bytes).To securely reproduce the data up to the data postamble field 1011, atiming error permitted in the read gate signal RGS, that is, a permittedpositional shift of the sector sync counter 302 becomes two bytes.Though it is permitted to set c10 to a value slightly larger than twobytes, if c10 is set to an excessively large value, a signal of the rearguard field 1012 which may be deteriorated is reproduced long.Therefore, this is not preferable because a problem may occur in thestability of PLL.

(Embodiment 3)

FIG. 10 is a block diagram showing a configuration example of a timinggeneration section 114 and its periphery according to a third embodimentof the present invention. In FIG. 10, because an address-mark detectionsection 111, demodulation section 112, address-error detection section113, and modulation section 115 have the same functions as thosedescribed in FIGS. 1, 3, and 8, the descriptions are omitted here.

The timing generation section 114 in FIG. 10 has a function ofgenerating various timing signals required to record and reproduce data,and is constituted of a reference-clock generation section 401, sectorsync counter 402, counted-value decoder 403, counted-value correctionsection 404, and recording/reproducing control section 405. Operationsof each functional block are described below.

The reference-clock generation section 401 generates a reference clockREFCLK3 serving as a criterion for recording and reproducing data. Inthis embodiment, it is assumed that the reference clock REFCLK3 has aone-channel-bit cycle of the data format shown in FIG. 2.

The sector sync counter 402 is a counter for counting the referenceclock REFCLK3 so that a counted value of the counter 402 shows a byteposition in one sector. In the case of the data format shown in FIG. 2,one sector has a length of 2,697 bytes, that is, a length of2,697×16=43,152 channel bits. Therefore, it is possible to constitutethe counter 402 of a 16-bit loop counter which counts from 0 to 43,151in accordance with a reference clock and then returns to 0. Moreover, itis necessary to synchronize the position of a light spot applied to anoptical disk 101 with a counted value of the sector sync counter 402.Therefore, a mechanism is used which corrects a counted value by using acounted-value correction pulse CCP3 and a count correction value CCV3.

The counted-value decoder 403 generates various timing signalssynchronizing with the data format of a sector by decoding a counteroutput CT03 output from the sector sync counter 402. In this case, whenthe decoder 403 receives a write enable signal WENBL from therecording/reproducing control section 405 when recording data, itoutputs a write gate signal WSG to a laser driving section 108 andmoreover outputs an enable signal ENBL necessary for modulation to themodulation section 115. Details of timing-signal generation in recordingdata are omitted here because the details are the same as the contentsdescribed in FIG. 8.

Moreover, when the counted-value decoder 403 receives a read enablesignal RENBL from the recording/reproducing control section 405 whenreproducing data, the counted-value decoder 403 outputs a read gatesignal RGS to a reproduction-signal processing section 106, andmoreover, generates a window signal WNS, which is necessary fordetection of a pre-sync code and the demodulation of data, and outputsthe signal WNS to the demodulation section 112. Because details oftiming signal generation when reproducing data are the same as thecontents described in FIG. 9, description of the details is omittedhere. The counted-value decoder 403 also generates an AM detectionwindow signal AMDWNS and feeds back the signal AMDWNS to thecounted-value correction section 404.

The counted-value correction section 404 outputs a counted-valuecorrection pulse CCP3 and a count correction value CCV3 by using an AMdetection pulse AMDD transmitted from the address mark detectionsection, CRCOK pulse transmitted from address error detection section113 and AM detection window signal AMDWNS transmitted from thecounted-value decoder 403.

The recording/reproducing control section 405 receives a recordingcommand RECCOM from a system controller 110 when recording data andoutputs a write enable signal WENBL in accordance with a predeterminedcriterion. Moreover, the recording/reproducing control section 405receives a reproduction command REPCOM from the system controller 110when reproducing data and outputs read enable signal RENBL in accordancewith a predetermined criterion. Output algorithms of a write enablesignal WENBL and read enable signal RENBL in each sector, that is,conditions for allowing data to be recorded and reproduced in eachsector will be described later.

FIG. 11 is an illustration for explaining a counted-value correctingoperation of the sector sync counter 402 in this embodiment. Theoperation example in FIG. 11 is characterized by controlling the countcorrection when detecting an address mark by using an AM detectionwindow AMDWNS as described below.

The first AM detection window AMDWNSa shown in FIG. 11(b) is a detectionwindow for an address mark field AMa in a first address field 1004a,which is set to H level by the counter output CT03 of the sector synccounter 402 in a range of 2Wa channel bits about a counted valuecorresponding to the terminal position of the address mark field AMa.When H pulse of the AM detection pulse AMDP in which an address mark i sdetected is output while the first AM detection window AMDWNSa is keptH-level, the counted-value correction section 404 outputs thecounted-value correction pulse CCP3 as H pulse and sets the countcorrection value CCV3 to A at the timing of deciding the countcorrection value CCV3 at the H-level portion of the counted-valuecorrection pulse CCP3.

In this example, the H-level period of the first AM detection windowAMDWNSa is ended at the time of detection of an address mark i n theaddress mark field AMa as illustrated (illustrated by pulse AMPD-a).This represents that the sector sync counter 402 is greatly shifted inthe early direction from an actual light-spot irradiation position atthe above point of time. Therefore, the counted-value correction pulseCCP3 is not output at the above point of time and the sector synccounter 402 is not corrected (shown by a dotted line, that is, CCP-mashown in FIG. 3 does not occur).

The second AM detection window AMDWNSb shown in FIG. 11(c) is adetection window for an address mark field AMb in an address field1004b, which is set to H level by the counter output CT03 of the sectorsync counter 402 in a range of 2Wb channel bits about a counted valuecorresponding to the terminal position, of the address mark field AMb.When an address mark is detected and H pulse of the AM detection pulseAMDP is output while the second AM detection window AMDWNSb is keptH-level (illustrated by AMDP-b), the counted-value correction section404 outputs the counted-value correction pulse CCP3 as an H pulse(illustrated by CCP-mb) and sets the count correction value CCV3 to C atthe timing of deciding the value CCV3 at the H-level portion of thecounted-value correction pulse CCP3.

In this example, the time of detection of an address mark in the addressmark field AMb is included in the H-level period of the second AMdetection window AMDWNSb as illustrated. Therefore, the counted-valuecorrection pulse CCP3 is output as an H pulse at the above point of timeto correct the sector sync counter 402.

The third AM detection window AMDWNSc shown in FIG. 11(d) is a detectionwindow for an address mark field AMc in the address field 1004c, whichis set to H level by the counter output CT03 of the sector sync counter402 in a range of 2Wc channel bits about a counted value correspondingto the terminal position of the address mark field AMc. As illustrated,when the H pulse of the AM detection pulse AMDP is output upon detectingan address mark while the third AM detection window AMDWNSc is keptH-level (illustrated by AMDP-c), the counted-value correction section404 outputs the counted-value correction pulse CCP3 as an H pulse(illustrated by CCP-mc) and sets the count correction value CCV3 to E atthe timing of deciding the value CCV3 at the H-level portion of thecounted-value correction pulse CCP3.

The fourth AM detection window AMDWNSd shown in FIG. 11(e) is adetection window for an address mark field AMd in an address field1604d, which is set to H level by the counter output CT03 of the sectorsync counter 402 in a range of 2Wd channel bits about a counted valuecorresponding to the terminal position of the address mark field AMd. Asillustrated, when an address mark is detected and the H pulse of the AMdetection pulse AMDP is output while the fourth AM detection windowMDWNSd is kept H-level (illustrated by AMDP-d), the counted-valuecorrection section 404 outputs the counted-value correction pulse CCP3as an H pulse (illustrated by CCP-md) and sets the count correctionvalue CCV3 to G at the timing of deciding the value CCV3 at the H-levelportion of the counted-value correction pulse CCP3.

As described above, by setting an individual AM detection window everyaddress mark field, it is possible to easily identify which addressfield in a sector a detected address mark is included in. Moreover,because a counted value is not corrected even if an address mark isdetected outside of an AM detection window, it is possible to preventthe synchronism of the sector sync counter 402 from being shifted due toerroneous detection of an address mark.

Furthermore, the counted-value correction by a CRCOK pulse is the sameas the example in FIG. 4. That is, any one place is recognized among(address information field+error detection code fields) of the addressfields 1004a, 1004b, 1004c, and 1004d, the counted-value correctionpulse CCP3 is output as an H pulse, and the count correction value CCV3is set to any one of B, D, F, and H.

It is preferable to decide parameters Wa, Wb, Wc, and Wd for decidingthe time width of each AM detection window in consideration of a shiftof the reference clock REFCLK3 from a track linear velocity everysector. Moreover, it is also permitted to set the parameters so as to beWa=Wb=Wc=Wd. Thereby, time widths of the AM detection windows areequalized each other.

It is also possible to control whether to perform counted-valuecorrection at the address-mark detection timing of a certain sectorcorrespondingly to whether a CRCOK pulse is output in a sector which islocated by M (M is a natural number) sectors before the sectorconcerned. For example, by setting M to 2 channel bits and Wa=Wb=Wc=Wdto 64 channel bits (i.e., 4bytes), a counted value is not corrected whenaddress information with no error is not obtained within two sectorsimmediately before. Moreover, a counted-value shift of the sector synccounter 402 permitted between two sectors becomes ±4 bytes. That is,when a shift of the reference clock REFCLK3 from a track linear velocitythat occurs between two sectors is within ±4 bytes, a counted value iscorrected at the address mark detection timing.

Thereby, when the sector sync counter 402 operates completelyindependently of a light-spot irradiation position, a counted value isnot corrected at the address-mark detection timing. Therefore, it ispossible to prevent the synchronism of the sector sync counter 402 frombeing shifted due to erroneous recognition of an address mark.

Next, the following describes the output algorithms of the write enablesignal WENBL and read enable signal RENBL in each sector by therecording/reproducing control section 405, that is, conditions forpermitting recording/reproducing of data in each sector.

FIG. 12 is a flowchart for explaining an example of datarecording/reproducing process in this embodiment. When a recordingcommand RECCOM or reproducing command REPCOM is output in a certainsector, a data recording/reproducing process is started by therecording/reproducing control section 405.

First, it is determined whether an address mark is detected in thesector concerned (step 1). At this time, when even one address mark isdetected in the sector concerned, it is regarded that an address mark isdetected. However, as described in FIG. 11, when an AM detection windowis provided, detection of an address mark outside the AM detectionwindow is excluded from the above definition.

When it is determined in step 1 that no address mark is detected,recording/reproducing of data in the subject sector is not permitted andthe program is advanced to a predetermined process when therecording/reproducing is impossible (case 0). In the case 0, there isconsidered an operation of shifting to a retry process for reproducingthe sector concerned once more when data is reproduced, or a substitutesector recording process, so-called alternation processing, withoutrecording the subject sector when data is recorded.

When it is determined in step 1 that an address mark is detected, it isdetermined whether no error is detected in address information, that is,whether a CRCOK pulse is output (step 2).

When it is determined in step 2 that CRCOK pulse is output, the programis advanced to a recording/reproducing process of the sector concerned(case 1). That is, the write enable signal WENBL is made active whendata is recorded, or the read enable signal RENBL is made active whendata is reproduced.

When it is determined in step 2 that no CRCOK pulse is output, it isdetermined whether no error is detected in address information in any ofM sectors (M is a natural number) before the subject sector, i.e.,whether a CRCOK pulse is output (step 3). In this case, it is preferableto set M to a value equal to the number of sectors for checking a CRCOKpulse serving as a criterion as to whether a counted value is correctedat the above address-mark detection timing.

When it is determined in step 3 that a CRCOK pulse is output, theprogram is advanced to a recording/reproducing process of the subjectsector (case 2). That is, the write enable signal WENBL is made activewhen data is recorded, and the read enable signal RENBL is made activewhen data is reproduced.

When it is determined in step 3 that no CROCK pulse is output, datarecording/reproducing of the subject sector is not permitted and theprogram is advanced to the predetermined recording/reproducingimpossible process (case 3). It is assumed that the processing in case 3is the same as the processing in case 0.

In the above-described processing steps, the recording/reproducingcontrol section 405 permits recording/reproducing of data in each sectorand outputs the write enable signal WENBL or read enable signal RENBL.Thereby, data is recorded or reproduced only in a sector in which acounted value of the sector sync counter 402 is corrected. Therefore, itis possible to accurately adjust the data recording/reproducing timingand keep the reliability of an apparatus high.

(Embodiment 4)

FIG. 13 is a block diagram showing a configuration example of aninformation; recording system according to the present invention. InFIG. 13, it is assumed that an optical disk 101 has a data format asshown in FIG. 2. Moreover, it is assumed that an optical disk drive 501basically has the configuration as shown in FIG. 1 and is able to atleast record data to a predetermined sector of the optical disk 101.

A host computer 502 stores various application programs for handling theinformation including AV data 510 and computer data 511 as a database soas to record information in the optical disk 101 by executing theseapplication programs and using the optical disk drive 501.

The optical disk drive 501 and the host computer 502 are connected eachother by a host interface 504 built in the drive 501 and a driveinterface 505 built in the computer 502 so that the informationincluding the AV data 510 and computer data 511 and commands forrecording the information can be transmitted.

A system controller 503 interprets a command transmitted via the hostinterface 504 and controls the whole of the optical disk 101 so as torecord the transmitted information in a predetermined sector of theoptical disk 101.

An i/o driver 506 issues a command to the optical disk drive 501 so thatinformation is correctly recorded to a predetermined sector of theoptical disk 101 and has a function of fetching the AV data 501 andcomputer data 511 via a file system 507 when necessity.

The file system 507 is software for handling the AV data 510 andcomputer data 511 as a plurality of file groups, adding a file attributecomprising file name, data length (number of data bytes), and type offile to each file, and performing the whole file management such assaving, deleting, and reading (opening) of a file.

The AV data 510 and computer data 511 fieldssumed as, for example, thedata stored in a storage medium such as a hard disk or flash ROM or datato be input from the outside of or to be output to the outside of theinformation recording system. As inputs/outputs to and from theinformation recording system, various types fieldssumed as shown below:previously digitized information, video signals input through a videocamera or microphone, data obtained by digitizing audio signals,character information and control instructions input through a keyboard,mouse, or touch panel, video and character information displayed on anexternal display unit such as a television monitor or liquid-crystaldisplay, and audio information output to a loudspeaker.

An application program A508 and application program B509 are softwarefor handing the AV data 510 and/or computer data 511 through the filesystem 507, processing information, and storing the informationnecessary for the optical disk 101 or other storage medium.

The host computer 502 is provided with a central processing unit CPU513for executing a program and performing calculation, a semiconductormemory used to temporarily store data or a program though notillustrated, or auxiliary memory such as a hard disk forstoring/memorizing data according to necessity, and the above hardwareis organically operated based on each application program, therebyallowing to execute the predetermined functions.

In general, field1-time performance is requested in many cases for theoperation of recording the AV data 510 in the optical disk 101. Forexample, a state is assumed that video information obtained bydigitizing a video signal supplied from a camera is handled as the AVdata 510 and the video information is recorded to the optical disk 101.In this case, to continuously record pictures supplied from the camerato the optical disk 101, it is requested to transmit the AV data 510from the host computer 502 to the optical disk drive 501 at apredetermined rate and record the data 510 in the optical disk 101, thatis, a predetermined transfer rate is requested.

Moreover, in the case of a certain type of AV data 510, even if an erroris included in a part of data, it is possible to repair the data 510 sothat the repair is not known by a user. Frame interpolation in a videosignal or linear interpolation by data samples before and after an audiosignal corresponds to the above repair.

Therefore, to record the real-time information such as the AV data 510continuously input to the optical disk 101, it is preferable to recordthe data without interruption, while permitting a small number of errorseven in a state where data errors easily occur due to a medium defect ofthe optical disk 101 or the like.

However, the real-time performance is not always requested for theoperation of recording the computer data 511 handled by a conventionalpersonal computer to an optical disk. Moreover, because a fatalinfluence is given to a system even if there is a small number of errorsin the computer data 511, occurrence of an data error cannot bepermitted.

In the above-described information recording system for recording theinformation including the AV data 510 having the realtime characteristicand the computer data 511 that cannot permit an error, several methodsfor improving the reliability of an apparatus are described below bylisting a plurality of examples. Specifically, a transfer-rate priorityrecording mode is used for the data which can permit a small number ofdata errors but for which field1-time characteristic is requested whilea transfer-rate non-priority recording mode is used for the data whichcannot permit an error.

The above transfer-rate priority recording mode is a mode for preventinga transfer rate from lowering by continuously recording data even in astate in which a small number of errors may occur when recording thedata in a sector. The state in which data errors may occur can beclassified into two states such as a state in which a data error occursand a state in which an address information error occurs.

As for the data error, an idea of assuring the quality of recorded databy verifying the data is used in the case of a conventional computermemory. Verifying is to verify whether the data has an error rate thatthe data can be sufficiently retrieved through error correction byreproducing data immediately after the data is recorded. As a verifyingmethod, there is considered a method in which data before demodulated iskept when e.g. recording, and the data is compared with data afterdemodulated to thereby measure a byte error rate and determine whetherthe byte error rate is equal to or less than a predetermined criterion.

However, due to performing the verifying operation, a problem occursthat the normal recording-sequence-execution time increases. This isbecause verifying requires the time for reproducing data and determiningthe quality of the reproduced data. Therefore, it is possible to preventa data transfer rate when recording from being deteriorated byperforming no verifying operation.

As for an address-information error, a conventional computer memory doesnot record data to a sector in which errors equal to or more than apredetermined criterion are detected in address information. Forexample, in the case of an optical disk having the data format shown inFIG. 2, because address information is recorded in each sector aplurality of times, it is used as a predetermined criterion that thenumber of pieces of address information reproduced with no error isequal to or more than a predetermined number among the plural pieces ofaddress information. Moreover, it is general to record data in the abovesector through retrying. As the content of retrying, it is general toperform the alteration processing for recording data in a predeterminedsubstitute sector when errors equal to or more than a predeterminedcriterion are detected as a result of recording data in the sectorhaving the same address again.

However, because the recording-sequence execution time is increased dueto the recording retrying or alteration processing applied to the samesector, a problem occurs that a data transfer rate for recording islowered. Therefore, by continuously performing recording even if errorsequal to or more than a predetermined criterion are detected in addressinformation, it is possible to prevent the data transfer rate in therecording from being deteriorated.

FIG. 14 is a flowchart showing an example of data recording in thisembodiment. In FIG. 14, when data is recorded to a predetermined sector,it is first determined whether errors equal to or more than apredetermined criterion are included in address information (step 1401).When errors are less than the predetermined criterion (arrow of NO), thedata is recorded to the subject sector (case 1401). When errors areequal to or more than the predetermined criterion (arrow of YES), it isdetermined whether the data to be recorded is transfer-rate prioritydata (step 1402). When the data is not transfer-rate priority data,recording of the data to the subject sector is interrupted and recordingretry is executed (case 1402). When the data is transfer-rate prioritydata, the data is recorded to the subject sector (case 1403).

By recording data in accordance with the flow as described above, onlythe transfer-rate-priority data is continuously recorded to the subjectsector (case 1403) in the case where errors equal to or more than thepredetermined criterion are included in the address information andwhere recording has been conventionally transferred to a retry process.That is, by selecting the data recording which has the highest priorityto the fact of not lowering a transfer rate as fortransfer-rate-priority data and selecting the data recording which haspriority to the fact of not causing data errors as for the data in whichit is unnecessary to have priority to a transfer rate, it is possible tomeet a performance requested to the both cases.

It is permitted that the sequence of step 1401 and step 1402 is reversedand advantages to be obtained are the same.

FIG. 15 shows another example of the data recording process in thisembodiment, which is a flowchart more minutely describing the processingin step 1401 in the flow in FIG. 14 as a specific example. In FIG. 15,when data is recorded to a predetermined sector, it is first determinedwhether an address mark is detected in the subject sector (step 1501).When no address mark is detected, the process is transferred to arecording retry process (Case 1501). When an address mark is detected,it is determined whether address information having no error is obtainedfrom the sector (that is, whether there is CRCOK) (step 1502). When theaddress information with no error is obtained, data is recorded to thesubject sector (Case 1). When even a piece of address information havingno error is not obtained, it is determined whether there is a sectorobtaining address information having no error in M (M is a naturalnumber) sectors before the sector concerned (step 1503).

When there is a not a sector obtaining address information with no errorin the period up to the precedent M sectors, the process goes to arecording retry process (Case 1502). When address information with noerror is obtained in the period up to the precedent M sectors, it isfurther determined whether the data to be recorded is transfer-ratepriority data (step 1504). When the data is not transfer-rate prioritydata (that is, when the data is transfer-rate-nonpriority data),recording of data in the subject sector is stopped and a recording retryprocess is executed (Case 1503). When the data is transfer-rate prioritydata, the data is recorded to the subject sector (Case 2).

By recording data in accordance with the flow as described above,similarly to the case of the example in FIG. 14, in the case where theprocess is conventionally transferred to a recording retry process whenerrors equal to or more than a predetermined criterion are included inthe address information, only transfer-rate priority data iscontinuously recorded to the subject sector without interrupting therecording.

Moreover, it is one of the features of this example to include adetermination whether an address mark is detected in criteria (step1501) so as not to record data to a sector from which no address mark isdetected. Thus, by combining the above feature with a method of decidingthe recording start timing in accordance with the address-mark detectiontiming as described in an optical-disk recording apparatus of thepresent invention, it is possible to record data at a high timingaccuracy.

Moreover, it is also one of the features of this example that the factthat at least address information with no error is obtained from any oneof sectors up to precedent M sectors (YES in step 1503) is used as acondition for recording data in the sector concerned even when addressinformation with no error is not obtained from the sector concerned.Thereby, data is recorded only to the sector for which the timing of thesector sync counter is corrected as described in the optical-diskrecording apparatus of the present invention. Therefore, it is possibleto accurately adjust the data recording/reproducing timing and keep thereliability of the apparatus high.

The flow of this example includes four types of determinationprocessings such as steps 1501, 1502, 1503, and 1504. However, thesequence of determination steps is not restricted to the example in FIG.14. For example, it is also possible to first execute the processing ofstep 1504 and in this case, the same advantage is obtained.

Then, as to how to determine the transfer-rate-priority data will bedescribed below in detail. First, how to determine whether to performthe transfer-rate-priority processing when the optical disk drive 501records data to the optical disk 101, the following two methods areconsidered.

(1) To make determination in accordance with the content of a commandissued to the optical disk drive 501 from the host computer 502.

(2) To make determination in accordance with the content of a mode setto the optical disk drive 501 from the host computer 502.

For the above method (1), a processing example is shown in FIG. 16. InFIG. 16, step 1601 for determining whether a command is for handling AVdata, and when it is determined that the command is a command forhandling AV data, transfer-rate-priority data recording process isexecuted (Case 1601). When it is determined that the command is not acommand for handling AV data, transfer-rate-nonpriority data recordingprocess is executed (Case 1602).

The transfer-rate-priority-data recording process represents theprocessing for continuously recording data to the subject sector withoutperforming a recording retry processing or alternation processing aspossible even if an error is detected in address information. Thetransfer-rate-nonpriority-data recording process represents theprocessing of retrying recording or performing alternation processing aspositively as possible by giving the highest priority to the fact thatno data error occurs when it is presumed that an error may occur.

A command (referred to as host command) for defining the content of acertain typical processing is prescribed between the host computer 502and the optical disk drive 501. To record the AV data 510 continuouslytransmitted, a first host command is prepared which assures a recordingdata transfer rate equal to or more than a predetermined criterion.Whereas, in the case of recording the data such as computer data 511whose transfer rate is not seriously considered but which cannot permitan error, a second command is prepared which does not have a conditionof a recording data transfer rate. Note that it is permitted to use afirst host command and a second host command different from each otheror to optionally change the same command.

To perform processing by including the method (1) in the flow in FIG. 14or 15, it is preferable to replace step 1402 with step 1601. Then,advantages same as described above are obtained.

Moreover, the method (1) makes it possible to easily changetransfer-rate priority and nonpriority processings in commands unit fromthe host computer 502 to the optical disk drive 501. Therefore, themethod (1) is effective for a case in which the AV data 510 and thecomputer data 511 are transferred in mixture.

In this case, the file system 507 shown in FIG. 13 conduct filemanagement by adding to the attribute of each file to be handled a codecapable of determining whether priority is given to a transfer rate. Forexample, it is preferable to add a transfer-rate-priority code to eachfile belonging to the AV data 510 and add a transfer-rate-nonprioritycode to each file belonging to the computer data 511.

Thus, even if a file included in the AV data 510 and a file included inthe computer data 511 are handled in mixture by an application A orapplication B, it is possible to easily select whether to issue thefirst host command or second host command to the optical disk drive 501by referring to the file attribute by the file system 507 or i/o driver506.

On the other hand, for the method (2), a processing is shown in FIG. 17.In FIG. 17, mode setting of whether to perform the transferrate-priorityprocessing is previously provided. It is preferable to perform the modesetting by setting a mode setting register 512 to the system controller503 built in the optical disk drive 501 and rewriting the contents ofthe mode setting register. Moreover, it is permitted to perform the modesetting by making the host computer 502 directly rewrite the modesetting register 512 through the driving interface 505 and hostinterface 504, or by providing a mode setting command from the hostcomputer 502 to the optical disk drive 501 so that the system controller503 receiving the mode setting command rewrites the mode settingregister.

In this case, a mode for performing the transfer-rate-priorityprocessing is referred to as a transfer-rate-priority mode and a modefor performing the transfer-rate-nonpriority processing is referred toas a transfer-rate-nonpriority mode. In the case of data recording, thesystem controller 503 first reads the content of the mode settingregister 512 and thereby determines which of the modes is set as adrive-mode (step 1701). When the drive mode is set to thetransfer-rate-priority mode, the controller 503 performs atransfer-rate-priority data recording process (case 1701). When thedrive mode is set to the transfer-rate-nonpriority mode, it performs atransfer-rate-nonpriority data recording process (Case 1702).

To perform processing by including the method (2) into the flow in FIG.14 or 15, it is preferable to replace step 1402 with step 1701. Then,advantages same as described above are obtained.

Moreover, the method (2) makes it possible to easily change theprocessing mode of the optical disk drive 501 to thetransfer-rate-priority mode or transfer-rate-nonpriority mode only byperforming the mode setting. Therefore, the method (2) is an effectivemethod in the case where it is possible to clearly separate anapplication for handling the AV data 510 and an application for handlingthe computer data 511 and where the both applications are not mixed.

In this case, it is assumed that the application program A 508 shown inFIG. 13 is a program for handling only the AV data 510 and theapplication program B 509 is a program for handling only computer data.Moreover, it is assumed that the above two applications cannot beexecuted at the same time.

When the application program A 508 is activated, the i/o driver 506first issues a command for setting the optical disk drive 501 to thetransfer-rate-priority mode. Then, when the AV data 510 recorded to theoptical disk 101, the optical disk drive 501 always operates in thetransfer-rate-priority mode.

When the application B 509 is activated, the i/o driver 506 first issuesa command for setting the optical disk drive 501 to thetransfer-rate-nonpriority mode. Then, when the computer data 511 isrecorded to the optical disk 101, the optical disk drive 501 alwaysoperates in the transfer-rate-nonpriority mode.

It is noted that the present invention is not restricted to the aboveembodiments but it is prescribed only in the contents set forth inclaims.

INDUSTRIAL APPLICABILITY

As described above, according to the configurations of the optical-diskrecording apparatuses or optical-disk reproducing apparatuses shown inthe embodiments of the present invention, it is possible to decide thedata-recording start timing or data-reproducing start timing inaccordance with the timing of detecting an address mark. Therefore, itis possible to record or reproduce data even in a sector having an errorin address information at a high accuracy, thereby improving thereliability of an apparatus.

Moreover, according to the configurations of the optical-disk recordingapparatuses or optical-disk reproducing apparatuses shown in theembodiments of the present invention, it is possible to determinewhether to record or reproduce data in a predetermined sector under thecondition that address information with no error is obtained from thesubject sector or that address information with no error is obtainedfrom at least a certain sector up to predetermined sectors preceding thesubject sector and an address mark is detected in the subject sector.Therefore, data is recorded or reproduced only in a sector capable ofgenerating an accurate timing by correcting the sector sync timing inthe subject sector, and thus the reliability of an apparatus can beimproved.

Furthermore, according to the optical-disk recording methods shown inthe embodiments of the present invention, it is determined whether datais transfer-rate-priority data or transfer-rate-nonpriority data whichcannot permit an error and only the transfer-rate-priority data isrecorded in a transfer-rate-priority recording process, it is possibleto minutely correspond to the performance of an apparatus requested foreach data.

Therefore, by applying the present invention to an information recordingsystem handling multimedia including computer data and real-time AVdata, it is possible to provide a high-speed and high-reliability systemand thus, the present invention is very effective in practical use.

1. An optical-disk recording apparatus for recording data in a datarecording field of an optical disk having a sector structure constitutedof a header field previously storing address information and a datarecording field for storing data, the header field including an addressmark field storing an address mark showing a beginning of addressinformation, an address information field storing address information,and an error detection code field storing an error detection code fordetecting an error in the address information field, said optical-diskrecording apparatus comprising: address-mark detection means fordetecting an address mark stored in the address mark field of thesector; and data-recording decision and control means for deciding andcontrolling a period of recording data in the data recording field ofthe sector; wherein said data-recording decision and control means usesan address-mark detection timing of said address-mark detection means indeciding and controlling the data recording period; wherein saiddata-recording decision and control means includes address-informationerror detection means for detecting a presence or absence of an error inthe address-information based on the address information and the errordetection code, and timing generation means for generating a recordingtiming signal for deciding a data recording operation by using theaddress-mark detection timing of detecting the address mark by saidaddress-mark detection means and a timing of detecting by saidaddress-information error detection means that there is no error in theaddress information; and wherein said data-recording decision andcontrol means, when recording data in the data recording field of apredetermined sector, permits data recording only where addressinformation having no error is obtained as a result of error detectionin the subject sector executed by said address-information errordetection means, and where at least one piece of address informationhaving no error is obtained in a predetermined number of sectorspreceding the subject sector as a result of error detection by saidaddress-information-error detection means and at least one address markis detected in the address mark field of the subject sector.
 2. Anoptical-disk recording apparatus for recording data in a data recordingfield of an optical disk having a sector structure constituted of aheader field previously storing address information and a data recordingfield for storing data, the header field including an address mark fieldstoring an address mark showing a beginning of address informaitoninformation, an address information field storing address information,and an error detection code field storing an error detection code fordetecting an error in the address information field, said optical-diskrecording apparatus comprising: address-mark detection means fordetecting an address mark stored in the address mark field of thesector; and data-recording decision and control means for deciding andcontrolling a period of recording data in the data recording field ofthe sector; wherein said data-recording decision and control means usesan address-mark detection timing of said address-mark detection means indeciding and controlling the data recording period; wherein saiddata-recording decision and control means includes address-informationerror detection means for detecting a presence or absence of an error inthe address information based on the address information and the errordetection code, and timing generation means for generating a recordingtiming signal for deciding a data recording operation by using theaddress-mark detection timing of detecting the address mark by saidaddress-mark detection means and a timing of detection detecting by saidaddress-information error detection means that there is no error in theaddress information; and wherein said timing generation means includeswherein said timing generation means includes clock generation means forgenerating a reference clock serving as a criterion of recording data,counting means for count-specifying a position in one sector by usingthe reference clock generated by said clock generation means,counted-value correction means for correcting the counted values of saidcounting means with predetermined values at the address-mark detectiontiming of detecting the address mark by said address-mark detectionmeans and the timing of detecting that there is no error in the addressinformation by said address-information-error detection means, anddecoding means for decoding the count output by said counting meanscorrected with the predetermined values to thereby produce therecording-timing signals.
 3. The optical-disk recording apparatusaccording to claim 2, wherein said decoding means decodes the countoutput by said counting means to generate an address-mark detectionwindow, permits said counted-value correction means to correct thecounted value when the address-mark detection timing detected by saidaddress-mark detection means is present within the address-markdetection window, and inhibits said counted-value correction means fromcorrecting the counted value when the address-mark detection timing isnot present within the address-mark detection window.
 4. Theoptical-disk recording apparatus according to claim 2, wherein: theheader field in each sector includes a plurality of address fields eachhaving an address mark field, an address information field, and an errordetection code field; and when said address-information error detectionmeans detects that there is no error in the address information in atleast one address field in each sector, said timing generation meansinhibits said counted-value correction means from correcting the countedvalue even if an address mark is detected in the subsequent addressfields thereafter in the subject sector.
 5. An optical-disk reproducingapparatus for reproducing data from a data recording field of an opticaldisk having a sector structure constituted of a header field previouslystoring address information and a data recording field for storing data,the header field includes including an address mark field storing anaddress mark showing a beginning of address information, an addressinformation field storing address information, and an error detectioncode field storing an error detection code for detecting an error in theaddress information field, said optical-disk reproducing apparatuscomprising: address-mark detection means for detecting an address markstored in the address mark field of the sector; and data-reproducingdecision and control means for deciding and controlling a period ofreproducing data from the data recording field of the sector; whereinsaid data-reproducing decision and control means uses an address-markdetection timing of said address-mark detection means in deciding andcontrolling the data reproducing period; wherein said data-reproducingdecision and control means includes address-information error detectionmeans for detecting a presence or absence of an error in the addressinformation based on the address information and the error detectioncode, and timing generation means for generating a reproducing timingsignal for deciding a data reproducing operation by using theaddress-mark detection timing detected by said address-mark detectionmeans and a timing detected by said address-information error detectionmeans of detecting that there is no error in the address information;and wherein said data-reproducing decision and control means, whenreproducing data from the data recording field of a predeterminedsector, permits data reproduction only where address information havingno error detected is obtained as a result of error detection in thesubject sector executed by said address-information error detectionmeans, and where at least one piece of address information having noerror detected is obtained in a predetermined number of sectorspreceding the subject sector as a result of error detection by saidaddress-information-error detection means and at least one address markis detected in the address mark field of the subject sector.
 6. Anoptical-disk reproducing apparatus for reproducing data from a datarecording field of an optical disk having a sector structure constitutedof a header field previously storing address informaiton information anda data recording field for storing data, the header field including anaddress mark field storing an address mark showing a beginning ofaddress information, an address information field storing addressinformation, and an error detection code field storing an errordetection code for detecting an error in the address information field,said optical-disk reproducing apparatus comprising: address-markdetection means for detecting an address mark stored in the address markfield of the sector; and data-reproducing decision and control means fordeciding and controlling a period of reproducing data from the datarecording field of the sector; wherein said data-reproducing decisionand control means uses an address-mark detection timing of saidaddress-mark detection means in deciding and controlling the datareproducing period; wherein said data-reproducing decision and controlmeans includes address-information error detection means for detectiondetecting a presence or absence of an error in the address informationbased on the address information and the error detection code, andtiming generation means for generating a reproducing timing signal fordeciding a data reproducing operation by using the address-markdetection timing detected by said address-mark detection means and atiming detected by said address-information error detection means ofdetecting that there is no error in the address information; and whereinsaid timing generation means includes: clock generation means forgenerating a reference clock serving as a criterion of reproducing data,counting means for count-specifying a position in one sector by usingthe reference clock generated by said clock generation means,counted-value correction means for correcting the counted values of saidcounting means with predetermined values at the address-mark detectiontiming of detecting the address mark by said address-mark detectionmeans and a timing of detecting that there is no error in the addressinformation by said address-information-error detection means, anddecoding means for decoding the count output by said counting meanscorrected with the predetermined values to thereby produce thereproducing-timing signals.
 7. The optical-disk reproducing apparatusaccording to claim 6, wherein said decoding means decodes said countoutput of said counting means to generate an address-mark detectionwindow, permits said counted-value correction means to correct thecounted value when the address-mark detection timing detected by saidaddress-mark detection means is present within the address-markdetection window, and inhibits said counted-value correction means fromcorrecting the counted value when the address-mark detection timing isnot present within the address-mark detection window.
 8. Theoptical-disk reproducing apparatus according to claim 6, wherein: theheader field in each sector includes a plurality of address fields eachhaving an address mark field, an address information field, and an errordetection code field; and when said address-information error detectionmeans detects that there is no error in the address information in atleast one address field in each sector, said timing generation meansinhibits said counted-value correction means from correcting the countedvalue even if an address mark is detected in the subsequent addressfields thereafter in the subject sector.
 9. An optical-disk recordingmethod for recording data in a data recording field of an optical diskhaving a sector structure constituted of a header field previouslystoring address information and a data recording field for storing data,the header field including an address mark field storing an address markshowing a beginning of address information, an address information fieldstoring address information, and an error detection code field storingan error detection code for detecting an error in the addressinformation field, said method comprising: detecting an address markstored in the address mark field of the sector; and deciding andcontrolling a period of recording data in the data recording field ofthe sector; wherein said deciding and controlling of the data recordingperiod uses an address-mark detection timing in deciding and controllingthe data recording period; wherein said deciding and controlling of thedata recording period includes detecting a presence or absence of anerror in the address information based on the address information andthe error detection code, and generating a recording timing signal fordeciding a data recording operation by using the address mark detectiontiming and a timing of detection in said detecting of the presence orabsence of the error that there is no error in the address information;and wherein said deciding and controlling of the data recording period,when recording period, when recording data in the data recording fieldof a predetermined sector, permits data recording only where addressinformation having no error detected is obtained as a result of errordetection in the subject sector executed in said detecting of thepresence or absence of an error, and where at least one piece of addressinformation having no error detected is obtained in a predeterminednumber of sectors preceding the subject sector as a result of errordetection and at least one address mark is detected in the address markfield of the subject sector.
 10. An optical-disk recording method forrecording data in a data recording field of an optical disk having asector structure constituted of a header field previously storingaddress information and a data recording field for storing data, theheader field including an address mark field storing an address markshowing a beginning of address information, an address information fieldstoring address information, and an error detection code field storingan error detection code for detecting code for detecting an error in theaddress information field, said optical-disk recording methodcomprising: detecting an address mark stored in the address mark fieldof the sector; and deciding and controlling a period of recording datain the data recording field of the sector; wherein said deciding andcontrolling of the data recording period uses an address-mark detectiontiming in deciding and controlling the data recording period; whereinsaid deciding and controlling of the data recording period includesdetecting a presence or absence of an error in the address informationbased on the address information and the error detection code, andgenerating a recording timing signal for deciding a data recordingoperation by using the address mark detection timing and a timing ofdetecting in said detecting of the presence of or absence of an errorthat there is no error in the address information; and wherein saidgenerating of the recording timing signal includes wherein saidgenerating of the recording timing signal includes generating areference clock serving as a criterion of recording data,count-specifying a position in one sector by using the reference clockgenerated in said generating of the reference clock, correcting thevalues counted in said count-specifying of the position in one sectorwith predetermined values at the address-mark detection timing ofdetecting the address mark and a timing of detecting that there is noerror in the address information executed in said detecting of thepresence or absence of an error, and decoding the counted value obtainedin said count-specifying of the position in one sector corrected withthe predetermined values to thereby produce the recording-timingsignals.
 11. The optical-disk recording method according to claim 10,wherein said decoding of the counted value decodes the counted valueobtained in said count-specifying of the position in one sector togenerate an address-mark detection window, permits the correction of thecounted value in said correcting of the counted values when theaddress-mark detection timing is present within the address-markdetection window, and inhibits said correcting of the counted valuesfrom correcting the counted value when the address-mark detection timingis not present within the address-mark detection window.
 12. Theoptical-disk recording method according to claim 10, wherein: the headerfield in each sector includes a plurality of address fields each havingan address mark field, an address information field, and an errordetection code field; and when said detecting of the presence or absenceof an error detects that there is no error in the address information inat least one address field in each sector, said generating of therecording timing signal inhibits the correction of the counted value insaid correcting of the counted values even if an address mark isdetected in the subsequent address fields thereafter in the subjectsector.
 13. An optical-disk reproducing method for reproducing data froma data recording field of an optical disk having a sector structureconstituted of a header field previously storing address information anda data recording field for storing data, the header field including anaddress mark field storing an address mark showing a beginning ofaddress information, an address information field storing addressinformation, and an error detection code field storing an errordetection code for detection detecting an error in the addressinformation field, said optical-disk reproducing method comprising:detecting an address mark stored in the address mark field of thesector; and deciding and controlling a period of reproducing data fromthe data recording field of the sector; wherein said deciding andcontrolling of the data reproducing period uses an address-markdetection timing in deciding and controlling the data reproducingperiod; wherein said deciding and controlling of the data reproducingperiod includes detecting a presence of or absence of an error in theaddress information based on the address information and the errordetection code, and generating a reproducing timing signal for decidinga data reproducing operation by using the address-mark detection timingand a timing of detecting in said detecting of the presence or absenceof an error that there is no error in the address information; andwherein said deciding and controlling of the data reproducing period,when reproducing data from the data recording field of a predeterminedsector, permits data reproduction only where address information havingno error detected is obtained as a result of error detection in thesubject sector executed in said detecting of the presence or absence ofan error, and where at least one piece of address information having noerror detected is obtained in a predetermined number of sectorspreceding the subject sector as a result of error detection and at leastone address mark is detected in the address mark field of the subjectsector.
 14. An optical-disk reproducing method for reproducing data froma data recording field of an optical disk having a sector structureconstituted of a header field previously storing address information anda data recording field for storing data, the header field including anaddress mark field storing an address mark showing a beginning ofaddress information, an address information field storing addressinformation, and an error detection code field storing an errordetection code for detecting an error in the address information field,said optical-disk reproducing method comprising: detecting an addressmark stored in the address mark field of the sector; and deciding andcontrolling a period of reproducing data from the data recording fieldof the sector; wherein said deciding and controlling of the datareproducing period uses an address-mark detection timing in deciding andcontrolling the data reproducing period; wherein said deciding andcontrolling of the data reproducing period uses an address-markdetection timing in deciding and controlling the data reproducingperiod; wherein said deciding and controlling of the data reproducingperiod includes detecting a presence or absence of an error in theaddress information based on the address information and the errordetection code, and generating a reproducing timing signal for decidinga data reproducing operation by using the address-mark detection timingand a timing of detecting in said detecting of the presence or absenceof an error that there is no error in the address information; andwherein said generating of the reproducing timing signal includeswherein said generating of the reproducing timing signal includesgenerating a reference clock serving as a criterion of reproducing data,count-specifying a position in one sector by using the reference clockgenerated in said generating of the reference clock, correcting thevalues counted in said count-specifying of the position in one sectorwith predetermined values at the address-mark detection timing ofdetecting the address mark and a timing of detecting that there is noerror in the address information executed in said detecting of thepresence or absence of an error, and decoding the counted value obtainedin said count-specifying of the position in one sector corrected withthe predetermined values to thereby produce the reproducing-timingsignals.
 15. The optical-disk reproducing method according to claim 14,wherein said decoding of the counted value decodes the counted valueobtained in said count-specifying of the position in one sector togenerate an address-mark detection window, and permits the correction ofthe counted value in said correcting of the counted values when theaddress-mark detection timing is present within the address-markdetection window, and inhibits said correcting of the counted valuesfrom correcting the counted value when the address-mark detection timingis not present within the address-mark detection window.
 16. Theoptical-disk reproducing method according to claim 14, wherein: theheader field in each sector includes a plurality of address fields eachhaving an address mark field, an address information field, and an errordetection code field, and when said detection detecting of the presenceor absence of an error detects that there is no error in the addressinformation in at least one address field in each sector, saidgenerating of the timing reproducing signal inhibits the correction ofthe counted value in said correcting of the counted values even if anaddress mark is detected in the subsequent address fields thereafter inthe subject sector.
 17. An information recording system for recordinginformation including transfer-rate-priority data andtransfer-rate-nonpriority data in mixture supplied from an external unitto an optical disk having a sector structure constituted of a headerfield previously storing address information and a data recording fieldfor storing data, said system comprising: an optical disk drive forrecording data to the data recording field in a predetermined sector ofthe optical disk; and determination means for determining whether theinformation to be recorded to the optical disk is transfer-rate-prioritydata or transfer-rate-nonpriority data; wherein when said determinationmeans determines that the information to be recorded to the optical diskis the transfer-rate-priority data, said optical disk drive is operableto record the information in the sector to record the data even if thereare errors equal to or more than a predetermined criterion in addressinformation in the sector to record the data: ; and wherein when saiddetermination means determines the data is the transfer-rate-nonprioritydata, said optical disk drive is operable to record the data in asubstitute sector without recording the data in the subject sector torecord the data if there are errors equal to or more than thepredetermined criterion in the subject sector.
 18. The informationrecording system according to claim 17, wherein: the header fieldincludes an address mark field storing an address mark showing abeginning of address information, an address information field storingaddress information, and an error detection code field storing an errordetection code for detecting an error in the address information field;said system further comprises address-mark detection means for detectingan address mark recorded in the address mark field of the subjectsector, and data-recording decision and control means for deciding andcontrolling a period of recording data to the data recording field ofthe subject sector; and wherein said data-recording decision and controlmeans uses an address-mark detection timing for deciding and controllingof the data recording period.
 19. The information recording systemaccording to claim 18, wherein said data-recording decision and controlmeans includes: address-information error detecting means for detectinga presence or absence of an error in the address information based onthe address information and the error detection code; and timinggeneration means for generating a recording timing signal for deciding adata recording operation by using the address mark detection timing anda timing of detecting that there is no error in the address information.20. The information recording system according to claim 19, wherein saiddata-recording decision and control means, when recording data in thedata recording field of a predetermined sector, determines whether ornot the supplied data is the transfer-rate-priority data where addressinformation having no error detected is obtained as a result of errordetection in the subject sector executed by said address-informationerror detection means, and where at least one piece of addressinformation having no error detected is obtained in a predeterminednumber of sectors preceding the subject sector as a result of executingthe address-information error detection by said address-informationerror detection means and at least one address mark is detected in theaddress mark field of the subject sector.
 21. The information recordingsystem according to claim 17, wherein said determination meansdetermines whether the information is transfer-rate-priority data ortransfer-rate-nonpriority data by interpreting whether a command is acommand for handling the transfer-rate-priority data or a command forhandling the transfer-rate-nonpriority data issued from an external unitto the optical disk drive.
 22. The information recording systemaccording to claim 17, wherein said determination means determineswhether the information is transfer-rate-priority data ortransfer-rate-nonpriority data depending on a content of a set mode setto the optical disk drive from an external unit (502) indicating whetherthe set mode is a mode for handling the transfer-rate-priority data or amode for handling the transfer-rate-nonpriority data.
 23. Theinformation recording system according to claim 17, further comprising afile system for filing the information to be handled, wherein each fileis provided with a file attribute showing transfer-rate-priority data ornot, and wherein said determination means determinestransfer-rate-priority data or transfer-rate-nonpriority data inaccordance with the fact that the attribute of each file provided by thefile system shows transfer rate priority or transfer rate nonpriority.24. An information recording method for recording data supplied from anexternal unit in a data recording field of an optical disk having asector structure constituted of a header field previously storingaddress information and a data recording field for storing data, saidmethod comprising: determining whether or not the information to berecorded to the optical disk is transfer-rate-priority data; andrecording the data in the sector to record the data even if there areerrors equal to or more than a predetermined criterion in addressinformation in the sector to record the data when the data to berecorded is determined in said determining to be thetransfer-rate-priority data, and recording the data in a substitutesector without recording the data in the subject sector to record thedata if there are errors equal to or more than the predeterminedcriterion in the subject sector when the data to be recorded isdetermined in said determining to be transfer-rate-nonpriority data. 25.The information recording method according to claim 24, wherein: theheader field includes an address mark field storing an address markshowing a beginning of address information, an address information fieldstoring address information, and an error detection code field storingan error detection code for detecting an error in the addressinformation field; wherein said method further comprises detecting anaddress mark recorded in the address mark field of the subject sector,and deciding and controlling a period of recording data to the datarecording field of the subject sector; wherein said deciding andcontrolling of the period of recording data uses an address-markdetection timing for deciding and controlling of the data recordingperiod.
 26. The information recording method according to claim 25,wherein said deciding and controlling of the data recording periodincludes: detecting a presence or absence of an error in the addressinformation based on the address information and the error detectioncode; and generating a recording timing signal for deciding a datarecording operation by using the address mark detection timing and atiming detected in said detecting of the presence or absence of an errorfor detecting that there is no error in the address information.
 27. Theinformation recording method according to claim 26, wherein saiddeciding and controlling of the data recording period, when recordingdata in the data recording field of a predetermined sector, determineswhether or not the supplied data is the transfer-rate-priority datawhere address information having no error detected is obtained as aresult of error detection in the subject sector executed in saiddetecting of the presence or absence of an error, and where at least onepiece of address information having no error detected is obtained in apredetermined number of sectors preceding the subject sector as a resultof executing the address-information error detection and at least oneaddress mark is detected in the address mark field of the subjectsector.
 28. The information recording method according to claim 24,wherein said determining determines whether the information istransfer-rate-priority data or transfer-rate-nonpriority data byinterpreting whether a command is a command for handling thetransfer-rate-priority data or a command for handling thetransfer-rate-nonpriority data issued from an external unit to theoptical disk drive.
 29. The information recording method according toclaim 24, wherein said determining determines whether the information istransfer-rate-priority data or transfer-rate-nonpriority data dependingon a content of a set mode set to the optical disk drive from anexternal unit indicating whether the set mode is a mode for handling thetransfer-rate-priority data or a mode for handling thetransfer-rate-nonpriority data.
 30. An information recording method forrecording data supplied from an external unit in a data recording fieldof an optical disk, said method comprising: determining whether or notthe data to be recorded to the data recording field istransfer-rate-priority data; and recording the data in the datarecording field to record the data even if there are errors equal to ormore than a predetermined criterion in address information in the datarecording field to record the data when the data to be recorded isdetermined in said determining to be the transfer-rate-priority data,and recording the data in a substitute field without recording the datain the data recording field to record the data if there are errors equalto or more than the predetermined criterion in the data recording fieldwhen the data to be recorded is determined in said determining to betransfer-rate-nonpriority data.
 31. The information recording methodaccording to claim 30, wherein said determining determines whether thedata to be recorded is transfer-rate-priority data ortransfer-rate-nonpriority data by interpreting whether a command is acommand for handling the transfer-rate-priority data or a command forhandling the transfer-rate-nonpriority data issued from an externalunit.
 32. The information recording method according to claim 30,wherein said determining determines whether the data to be recorded istransfer-rate-priority data or transfer-rate-nonpriority data dependingon a content of a set mode set from an external unit indicating whetherthe set mode is a mode for handling the transfer-rate-priority data or amode for handling the transfer-rate-nonpriority data.